Cleanup: remove workarounds and version checks for unsupported compilers

Match minimum supported versions from the WIKI [0] by raising them to:

- GCC 9.3.1
- CLANG 8.0
- MVCS 2019 (16.9.16 / 1928)

Details:

- Add CMake checks that ensure supported compiler versions early on.
- Previously GCC per-processor version checks served to exclude
  `__clang__`, in some cases this has been replaced by explicitly
  excluding `__clang__`. This was needed as CLANG treated some of these
  flags differently to GCC, causing the build to fail.
- Remove USE_APPLE_OMP_FIX GCC-4.2 OpenMP workaround.
- Remove linking error workaround for old MSVC versions.

[0]: https://wiki.blender.org/wiki/Building_Blender

Reviewed by: brecht, LazyDodo

Ref D16068

15 files changed, 52 insertions, 139 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7a48caa4eae..ef3309ded48 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -112,6 +112,25 @@ enable_testing()
 
 
 # -----------------------------------------------------------------------------
+# Test Compiler Support
+#
+# Keep in sync with: https://wiki.blender.org/wiki/Building_Blender
+
+if(CMAKE_COMPILER_IS_GNUCC)
+  if("${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "9.3.1")
+    message(FATAL_ERROR "The minimum supported version of GCC is 9.3.1")
+  endif()
+elseif(CMAKE_C_COMPILER_ID MATCHES "Clang")
+  if(CMAKE_COMPILER_IS_GNUCC AND ("${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "8.0"))
+    message(FATAL_ERROR "The minimum supported version of CLANG is 8.0")
+  endif()
+elseif(CMAKE_CXX_COMPILER_ID MATCHES MSVC)
+  if(MSVC_VERSION VERSION_LESS "1928")
+    message(FATAL_ERROR "The minimum supported version of MSVC is 2019 (16.9.16)")
+  endif()
+endif()
+
+# -----------------------------------------------------------------------------
 # Test Compiler/Library Features
 
 include(build_files/cmake/have_features.cmake)
@@ -1428,22 +1447,13 @@ if(CMAKE_COMPILER_IS_GNUCC)
   add_check_c_compiler_flag(C_WARNINGS C_WARN_NO_NULL -Wnonnull)
   add_check_c_compiler_flag(C_WARNINGS C_WARN_ABSOLUTE_VALUE -Wabsolute-value)
 
-  # gcc 4.2 gives annoying warnings on every file with this
-  if(NOT "${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "4.3")
-    add_check_c_compiler_flag(C_WARNINGS C_WARN_UNINITIALIZED -Wuninitialized)
-    add_check_cxx_compiler_flag(CXX_WARNINGS CXX_WARN_UNINITIALIZED -Wuninitialized)
-  endif()
+  add_check_c_compiler_flag(C_WARNINGS C_WARN_UNINITIALIZED -Wuninitialized)
+  add_check_cxx_compiler_flag(CXX_WARNINGS CXX_WARN_UNINITIALIZED -Wuninitialized)
 
-  # versions before gcc4.6 give many BLI_math warnings
-  if(NOT "${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "4.6")
-    add_check_c_compiler_flag(C_WARNINGS C_WARN_REDUNDANT_DECLS       -Wredundant-decls)
-    add_check_cxx_compiler_flag(CXX_WARNINGS CXX_WARN_REDUNDANT_DECLS -Wredundant-decls)
-  endif()
+  add_check_c_compiler_flag(C_WARNINGS C_WARN_REDUNDANT_DECLS       -Wredundant-decls)
+  add_check_cxx_compiler_flag(CXX_WARNINGS CXX_WARN_REDUNDANT_DECLS -Wredundant-decls)
 
-  # versions before gcc4.8 include global name-space.
-  if(NOT "${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "4.8")
-    add_check_c_compiler_flag(C_WARNINGS C_WARN_SHADOW -Wshadow)
-  endif()
+  add_check_c_compiler_flag(C_WARNINGS C_WARN_SHADOW -Wshadow)
 
   # disable because it gives warnings for printf() & friends.
   # add_check_c_compiler_flag(C_WARNINGS C_WARN_DOUBLE_PROMOTION -Wdouble-promotion -Wno-error=double-promotion)
@@ -1470,11 +1480,7 @@ if(CMAKE_COMPILER_IS_GNUCC)
   add_check_cxx_compiler_flag(CXX_WARNINGS CXX_WARN_FORMAT_SIGN -Wformat-signedness)
   add_check_cxx_compiler_flag(CXX_WARNINGS CXX_WARN_RESTRICT -Wrestrict)
   add_check_cxx_compiler_flag(CXX_WARNINGS CXX_WARN_NO_SUGGEST_OVERRIDE  -Wno-suggest-override)
-
-  # gcc 4.2 gives annoying warnings on every file with this
-  if(NOT "${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "4.3")
-    add_check_cxx_compiler_flag(CXX_WARNINGS CXX_WARN_UNINITIALIZED -Wuninitialized)
-  endif()
+  add_check_cxx_compiler_flag(CXX_WARNINGS CXX_WARN_UNINITIALIZED -Wuninitialized)
 
   # causes too many warnings
   if(NOT APPLE)
@@ -1483,11 +1489,8 @@ if(CMAKE_COMPILER_IS_GNUCC)
   endif()
 
   # Use 'ATTR_FALLTHROUGH' macro to suppress.
-  if(CMAKE_COMPILER_IS_GNUCC AND (NOT "${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "7.0"))
-    add_check_c_compiler_flag(C_WARNINGS C_WARN_IMPLICIT_FALLTHROUGH -Wimplicit-fallthrough=5)
-    add_check_cxx_compiler_flag(CXX_WARNINGS CXX_WARN_IMPLICIT_FALLTHROUGH -Wimplicit-fallthrough=5)
-  endif()
-
+  add_check_c_compiler_flag(C_WARNINGS C_WARN_IMPLICIT_FALLTHROUGH -Wimplicit-fallthrough=5)
+  add_check_cxx_compiler_flag(CXX_WARNINGS CXX_WARN_IMPLICIT_FALLTHROUGH -Wimplicit-fallthrough=5)
 
   # ---------------------
   # Suppress Strict Flags
@@ -1517,9 +1520,7 @@ if(CMAKE_COMPILER_IS_GNUCC)
   add_check_cxx_compiler_flag(CXX_REMOVE_STRICT_FLAGS CXX_WARN_NO_UNUSED_VARIABLE     -Wno-unused-variable)
   add_check_cxx_compiler_flag(CXX_REMOVE_STRICT_FLAGS CXX_WARN_NO_UNUSED_VARIABLE     -Wno-uninitialized)
 
-  if(CMAKE_COMPILER_IS_GNUCC AND (NOT "${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "7.0"))
-    add_check_c_compiler_flag(C_REMOVE_STRICT_FLAGS C_WARN_NO_IMPLICIT_FALLTHROUGH    -Wno-implicit-fallthrough)
-  endif()
+  add_check_c_compiler_flag(C_REMOVE_STRICT_FLAGS C_WARN_NO_IMPLICIT_FALLTHROUGH    -Wno-implicit-fallthrough)
 
   if(NOT APPLE)
     add_check_c_compiler_flag(C_REMOVE_STRICT_FLAGS C_WARN_NO_ERROR_UNUSED_BUT_SET_VARIABLE -Wno-error=unused-but-set-variable)
@@ -1609,6 +1610,8 @@ elseif(CMAKE_C_COMPILER_ID MATCHES "MSVC")
     "/w34062"  # switch statement contains 'default' but no 'case' labels
     "/w34115"  # 'type' : named type definition in parentheses
     "/w34189"  # local variable is initialized but not referenced
+    # see https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/c5038?view=vs-2017
+    "/w35038"  # order of initialization in c++ constructors
     # disable:
     "/wd4018"  # signed/unsigned mismatch
     "/wd4146"  # unary minus operator applied to unsigned type, result still unsigned
@@ -1630,11 +1633,6 @@ elseif(CMAKE_C_COMPILER_ID MATCHES "MSVC")
     "/we4431"  # missing type specifier - int assumed
   )
 
-  if(MSVC_VERSION GREATER_EQUAL 1911)
-    # see https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/c5038?view=vs-2017
-    string(APPEND _WARNINGS " /w35038") # order of initialization in c++ constructors
-  endif()
-
   string(REPLACE ";" " " _WARNINGS "${_WARNINGS}")
   set(C_WARNINGS "${_WARNINGS}")
   set(CXX_WARNINGS "${_WARNINGS}")
@@ -1686,7 +1684,7 @@ set(CMAKE_CXX_EXTENSIONS OFF)
 # Make MSVC properly report the value of the __cplusplus preprocessor macro
 # Available MSVC 15.7 (1914) and up, without this it reports 199711L regardless
 # of the C++ standard chosen above.
-if(MSVC AND MSVC_VERSION GREATER 1913)
+if(MSVC)
   string(APPEND CMAKE_CXX_FLAGS " /Zc:__cplusplus")
 endif()
 
diff --git a/build_files/cmake/macros.cmake b/build_files/cmake/macros.cmake
index d41024759fc..3acea19079b 100644
--- a/build_files/cmake/macros.cmake
+++ b/build_files/cmake/macros.cmake
@@ -1190,8 +1190,6 @@ macro(openmp_delayload
     if(WITH_OPENMP)
       if(MSVC_CLANG)
         set(OPENMP_DLL_NAME "libomp")
-      elseif(MSVC_VERSION EQUAL 1800)
-        set(OPENMP_DLL_NAME "vcomp120")
       else()
         set(OPENMP_DLL_NAME "vcomp140")
       endif()
diff --git a/build_files/cmake/platform/platform_unix.cmake b/build_files/cmake/platform/platform_unix.cmake
index bfbc6b76b40..f640f7f7650 100644
--- a/build_files/cmake/platform/platform_unix.cmake
+++ b/build_files/cmake/platform/platform_unix.cmake
@@ -26,11 +26,6 @@ if(NOT DEFINED LIBDIR)
     else()
       set(WITH_LIBC_MALLOC_HOOK_WORKAROUND True)
     endif()
-
-    if(CMAKE_COMPILER_IS_GNUCC AND
-       CMAKE_C_COMPILER_VERSION VERSION_LESS 9.3)
-      message(FATAL_ERROR "GCC version must be at least 9.3 for precompiled libraries, found ${CMAKE_C_COMPILER_VERSION}")
-    endif()
   endif()
 
   # Avoid namespace pollustion.
diff --git a/build_files/cmake/platform/platform_win32.cmake b/build_files/cmake/platform/platform_win32.cmake
index eeec4760b80..866d0bede3d 100644
--- a/build_files/cmake/platform/platform_win32.cmake
+++ b/build_files/cmake/platform/platform_win32.cmake
@@ -74,27 +74,6 @@ add_definitions(-DWIN32)
 add_compile_options("$<$<C_COMPILER_ID:MSVC>:/utf-8>")
 add_compile_options("$<$<CXX_COMPILER_ID:MSVC>:/utf-8>")
 
-# Minimum MSVC Version
-if(CMAKE_CXX_COMPILER_ID MATCHES MSVC)
-  if(MSVC_VERSION EQUAL 1800)
-    set(_min_ver "18.0.31101")
-    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS ${_min_ver})
-      message(FATAL_ERROR
-        "Visual Studio 2013 (Update 4, ${_min_ver}) required, "
-        "found (${CMAKE_CXX_COMPILER_VERSION})")
-    endif()
-  endif()
-  if(MSVC_VERSION EQUAL 1900)
-    set(_min_ver "19.0.24210")
-    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS ${_min_ver})
-      message(FATAL_ERROR
-        "Visual Studio 2015 (Update 3, ${_min_ver}) required, "
-        "found (${CMAKE_CXX_COMPILER_VERSION})")
-    endif()
-  endif()
-endif()
-unset(_min_ver)
-
 # needed for some MSVC installations
 # 4099 : PDB 'filename' was not found with 'object/library'
 string(APPEND CMAKE_EXE_LINKER_FLAGS " /SAFESEH:NO /ignore:4099")
@@ -158,7 +137,7 @@ endif()
 
 
 # C++ standards conformace (/permissive-) is available on msvc 15.5 (1912) and up
-if(MSVC_VERSION GREATER 1911 AND NOT MSVC_CLANG)
+if(NOT MSVC_CLANG)
   string(APPEND CMAKE_CXX_FLAGS " /permissive-")
   # Two-phase name lookup does not place nicely with OpenMP yet, so disable for now
   string(APPEND CMAKE_CXX_FLAGS " /Zc:twoPhase-")
@@ -218,7 +197,7 @@ unset(SYMBOL_FORMAT)
 unset(SYMBOL_FORMAT_RELEASE)
 
 # JMC is available on msvc 15.8 (1915) and up
-if(MSVC_VERSION GREATER 1914 AND NOT MSVC_CLANG)
+if(NOT MSVC_CLANG)
   string(APPEND CMAKE_CXX_FLAGS_DEBUG " /JMC")
 endif()
 
@@ -251,9 +230,6 @@ if(NOT DEFINED LIBDIR)
   elseif(MSVC_VERSION GREATER 1919)
     message(STATUS "Visual Studio 2019 detected.")
     set(LIBDIR ${CMAKE_SOURCE_DIR}/../lib/${LIBDIR_BASE}_vc15)
-  elseif(MSVC_VERSION GREATER 1909)
-    message(STATUS "Visual Studio 2017 detected.")
-    set(LIBDIR ${CMAKE_SOURCE_DIR}/../lib/${LIBDIR_BASE}_vc15)
   endif()
 else()
   message(STATUS "Using pre-compiled LIBDIR: ${LIBDIR}")
@@ -264,10 +240,8 @@ endif()
 
 include(platform_old_libs_update)
 
-if(CMAKE_GENERATOR MATCHES "^Visual Studio.+" AND # Only supported in the VS IDE
-   MSVC_VERSION GREATER_EQUAL 1924            AND # Supported for 16.4+
-   WITH_CLANG_TIDY                                # And Clang Tidy needs to be on
-  )
+# Only supported in the VS IDE & Clang Tidy needs to be on.
+if(CMAKE_GENERATOR MATCHES "^Visual Studio.+" AND WITH_CLANG_TIDY)
   set(CMAKE_VS_GLOBALS
     "RunCodeAnalysis=false"
     "EnableMicrosoftCodeAnalysis=false"
@@ -278,8 +252,7 @@ endif()
 
 # Mark libdir as system headers with a lower warn level, to resolve some warnings
 # that we have very little control over
-if(MSVC_VERSION GREATER_EQUAL 1914 AND # Available with 15.7+
-   NOT MSVC_CLANG                  AND # But not for clang
+if(NOT MSVC_CLANG                  AND # Available with MSVC 15.7+ but not for CLANG.
    NOT WITH_WINDOWS_SCCACHE        AND # And not when sccache is enabled
    NOT VS_CLANG_TIDY)                  # Clang-tidy does not like these options
   add_compile_options(/experimental:external /external:templates- /external:I "${LIBDIR}" /external:W0)
diff --git a/extern/gflags/CMakeLists.txt b/extern/gflags/CMakeLists.txt
index 4f2fce3778b..63749aad46d 100644
--- a/extern/gflags/CMakeLists.txt
+++ b/extern/gflags/CMakeLists.txt
@@ -3,9 +3,7 @@
 
 # Too noisy for code we don't maintain.
 if(CMAKE_COMPILER_IS_GNUCC)
-  if(NOT "${CMAKE_CXX_COMPILER_VERSION}" VERSION_LESS "8.0")
-    add_cxx_flag("-Wno-cast-function-type")
-  endif()
+  add_cxx_flag("-Wno-cast-function-type")
 endif()
 
 set(INC
diff --git a/intern/atomic/intern/atomic_ops_utils.h b/intern/atomic/intern/atomic_ops_utils.h
index 533cfbe9e1f..1c4cef564c3 100644
--- a/intern/atomic/intern/atomic_ops_utils.h
+++ b/intern/atomic/intern/atomic_ops_utils.h
@@ -106,8 +106,7 @@
 /* Copied from BLI_utils... */
 /* C++ can't use _Static_assert, expects static_assert() but c++0x only,
  * Coverity also errors out. */
-#if (!defined(__cplusplus)) && (!defined(__COVERITY__)) && \
-    (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 406)) /* gcc4.6+ only */
+#if (!defined(__cplusplus)) && (!defined(__COVERITY__)) && (defined(__GNUC__)) /* GCC only. */
 #  define ATOMIC_STATIC_ASSERT(a, msg) __extension__ _Static_assert(a, msg);
 #else
 /* Code adapted from http://www.pixelbeat.org/programming/gcc/static_assert.html */
diff --git a/intern/atomic/tests/atomic_test.cc b/intern/atomic/tests/atomic_test.cc
index 37a66cf0e9c..6c0e96b9d91 100644
--- a/intern/atomic/tests/atomic_test.cc
+++ b/intern/atomic/tests/atomic_test.cc
@@ -6,12 +6,8 @@
 #include "testing/testing.h"
 
 #ifdef __GNUC__
-#  if (__GNUC__ * 100 + __GNUC_MINOR__) >= 406 /* gcc4.6+ only */
-#    pragma GCC diagnostic error "-Wsign-compare"
-#  endif
-#  if (__GNUC__ * 100 + __GNUC_MINOR__) >= 408
-#    pragma GCC diagnostic error "-Wsign-conversion"
-#  endif
+#  pragma GCC diagnostic error "-Wsign-compare"
+#  pragma GCC diagnostic error "-Wsign-conversion"
 #endif
 
 /* -------------------------------------------------------------------- */
diff --git a/source/blender/blenlib/BLI_assert.h b/source/blender/blenlib/BLI_assert.h
index 4a7fae6e98c..4292620e462 100644
--- a/source/blender/blenlib/BLI_assert.h
+++ b/source/blender/blenlib/BLI_assert.h
@@ -67,7 +67,7 @@ void _BLI_assert_unreachable_print(const char *file, int line, const char *funct
 #  define BLI_STATIC_ASSERT(a, msg) static_assert(a, msg);
 #elif defined(_MSC_VER)
 /* Visual Studio */
-#  if (_MSC_VER > 1910) && !defined(__clang__)
+#  if !defined(__clang__)
 #    define BLI_STATIC_ASSERT(a, msg) static_assert(a, msg);
 #  else
 #    define BLI_STATIC_ASSERT(a, msg) _STATIC_ASSERT(a);
diff --git a/source/blender/blenlib/BLI_compiler_attrs.h b/source/blender/blenlib/BLI_compiler_attrs.h
index 99f0aa9f049..9ee626296cb 100644
--- a/source/blender/blenlib/BLI_compiler_attrs.h
+++ b/source/blender/blenlib/BLI_compiler_attrs.h
@@ -25,7 +25,7 @@
 #endif
 
 /* never returns NULL */
-#if (__GNUC__ * 100 + __GNUC_MINOR__) >= 409 /* gcc4.9+ only */
+#ifdef __GNUC__
 #  define ATTR_RETURNS_NONNULL __attribute__((returns_nonnull))
 #else
 #  define ATTR_RETURNS_NONNULL
@@ -39,14 +39,14 @@
 #endif
 
 /* hint to treat any non-null function return value cannot alias any other pointer */
-#if (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 403))
+#ifdef __GNUC__
 #  define ATTR_MALLOC __attribute__((malloc))
 #else
 #  define ATTR_MALLOC
 #endif
 
 /* the function return value points to memory (2 args for 'size * tot') */
-#if (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 403))
+#ifdef __GNUC__
 #  define ATTR_ALLOC_SIZE(args...) __attribute__((alloc_size(args)))
 #else
 #  define ATTR_ALLOC_SIZE(...)
@@ -69,7 +69,7 @@
 
 /* Use to suppress '-Wimplicit-fallthrough' (in place of 'break'). */
 #ifndef ATTR_FALLTHROUGH
-#  if defined(__GNUC__) && (__GNUC__ >= 7) /* gcc7.0+ only */
+#  ifdef __GNUC__
 #    define ATTR_FALLTHROUGH __attribute__((fallthrough))
 #  else
 #    define ATTR_FALLTHROUGH ((void)0)
diff --git a/source/blender/blenlib/BLI_endian_switch_inline.h b/source/blender/blenlib/BLI_endian_switch_inline.h
index ce44348d4dd..32cb0f234f2 100644
--- a/source/blender/blenlib/BLI_endian_switch_inline.h
+++ b/source/blender/blenlib/BLI_endian_switch_inline.h
@@ -26,7 +26,7 @@ BLI_INLINE void BLI_endian_switch_int16(short *val)
 }
 BLI_INLINE void BLI_endian_switch_uint16(unsigned short *val)
 {
-#if (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 408)) /* gcc4.8+ only */
+#ifdef __GNUC__
   *val = __builtin_bswap16(*val);
 #else
   unsigned short tval = *val;
diff --git a/source/blender/blenlib/BLI_math_inline.h b/source/blender/blenlib/BLI_math_inline.h
index bf91c9108a9..b190b022a88 100644
--- a/source/blender/blenlib/BLI_math_inline.h
+++ b/source/blender/blenlib/BLI_math_inline.h
@@ -28,8 +28,8 @@ extern "C" {
 #  define MALWAYS_INLINE
 #endif
 
-/* gcc 4.6 (supports push/pop) */
-#if (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 406))
+/* Check for GCC push/pop pragma support. */
+#ifdef __GNUC__
 #  define BLI_MATH_GCC_WARN_PRAGMA 1
 #endif
 
diff --git a/source/blender/blenlib/BLI_strict_flags.h b/source/blender/blenlib/BLI_strict_flags.h
index 8489871d5da..cc5b5dce363 100644
--- a/source/blender/blenlib/BLI_strict_flags.h
+++ b/source/blender/blenlib/BLI_strict_flags.h
@@ -9,16 +9,12 @@
  */
 
 #ifdef __GNUC__
-#  if (__GNUC__ * 100 + __GNUC_MINOR__) >= 406 /* gcc4.6+ only */
+/* NOTE(@campbellbarton): CLANG behaves slightly differently to GCC,
+ * these can be enabled but do so carefully as they can introduce build-errors.  */
+#  if !defined(__clang__)
 #    pragma GCC diagnostic error "-Wsign-compare"
-#  endif
-#  if __GNUC__ >= 6 /* gcc6+ only */
 #    pragma GCC diagnostic error "-Wconversion"
-#  endif
-#  if (__GNUC__ * 100 + __GNUC_MINOR__) >= 408
-/* gcc4.8+ only (behavior changed to ignore globals). */
 #    pragma GCC diagnostic error "-Wshadow"
-/* older gcc changed behavior with ternary */
 #    pragma GCC diagnostic error "-Wsign-conversion"
 #  endif
 /* pedantic gives too many issues, developers can define this for own use */
diff --git a/source/blender/blenlib/BLI_winstuff.h b/source/blender/blenlib/BLI_winstuff.h
index 7201e1bb4a1..34f1b1a68f1 100644
--- a/source/blender/blenlib/BLI_winstuff.h
+++ b/source/blender/blenlib/BLI_winstuff.h
@@ -48,11 +48,6 @@ extern "C" {
 #  define S_ISDIR(x) (((x)&_S_IFDIR) == _S_IFDIR)
 #endif
 
-/* Defines for using ISO C++ conferment names. */
-#if !defined(_MSC_VER) || _MSC_VER < 1900
-#  define snprintf _snprintf
-#endif
-
 #if defined(_MSC_VER)
 #  define R_OK 4
 #  define W_OK 2
diff --git a/source/blender/blenlib/intern/threads.cc b/source/blender/blenlib/intern/threads.cc
index 156f2a7b338..f99a27c2475 100644
--- a/source/blender/blenlib/intern/threads.cc
+++ b/source/blender/blenlib/intern/threads.cc
@@ -37,17 +37,6 @@
 
 #include "atomic_ops.h"
 
-#if defined(__APPLE__) && defined(_OPENMP) && (__GNUC__ == 4) && (__GNUC_MINOR__ == 2) && \
-    !defined(__clang__)
-#  define USE_APPLE_OMP_FIX
-#endif
-
-#ifdef USE_APPLE_OMP_FIX
-/* ************** libgomp (Apple gcc 4.2.1) TLS bug workaround *************** */
-extern pthread_key_t gomp_tls_key;
-static void *thread_tls_data;
-#endif
-
 /**
  * Basic Thread Control API
  * ========================
@@ -153,15 +142,7 @@ void BLI_threadpool_init(ListBase *threadbase, void *(*do_thread)(void *), int t
     }
   }
 
-  uint level = atomic_fetch_and_add_u(&thread_levels, 1);
-  if (level == 0) {
-#ifdef USE_APPLE_OMP_FIX
-    /* Workaround for Apple gcc 4.2.1 OMP vs background thread bug,
-     * we copy GOMP thread local storage pointer to setting it again
-     * inside the thread that we start. */
-    thread_tls_data = pthread_getspecific(gomp_tls_key);
-#endif
-  }
+  atomic_fetch_and_add_u(&thread_levels, 1);
 }
 
 int BLI_available_threads(ListBase *threadbase)
@@ -194,13 +175,6 @@ int BLI_threadpool_available_thread_index(ListBase *threadbase)
 static void *tslot_thread_start(void *tslot_p)
 {
   ThreadSlot *tslot = (ThreadSlot *)tslot_p;
-
-#ifdef USE_APPLE_OMP_FIX
-  /* Workaround for Apple gcc 4.2.1 OMP vs background thread bug,
-   * set GOMP thread local storage pointer which was copied beforehand */
-  pthread_setspecific(gomp_tls_key, thread_tls_data);
-#endif
-
   return tslot->do_thread(tslot->callerdata);
 }
 
diff --git a/source/blender/imbuf/intern/openexr/openexr_api.cpp b/source/blender/imbuf/intern/openexr/openexr_api.cpp
index 7a94a938861..8468aaa70b9 100644
--- a/source/blender/imbuf/intern/openexr/openexr_api.cpp
+++ b/source/blender/imbuf/intern/openexr/openexr_api.cpp
@@ -73,15 +73,6 @@
 
 #include "MEM_guardedalloc.h"
 
-extern "C" {
-
-/* The following prevents a linking error in debug mode for MSVC using the libs in SVN. */
-#if defined(WITH_OPENEXR) && defined(_WIN32) && defined(DEBUG) && _MSC_VER < 1900
-_CRTIMP void __cdecl _invalid_parameter_noinfo(void)
-{
-}
-#endif
-}
 #include "BLI_blenlib.h"
 #include "BLI_fileops.h"
 #include "BLI_math_color.h"