CMake: support building with musl libc

Instead of using macros like GLIBC we can use the CMake build
systems internal functions to check if some header or functions are
present on the running system's libc.

Add ./build_files/cmake/have_features.cmake to add checks for
platform features which can be used to set defines for source
files that require them.

Reviewed By: campbellbarton

Ref D15696

1 files changed, 33 insertions, 0 deletions

diff --git a/build_files/cmake/have_features.cmake b/build_files/cmake/have_features.cmake
new file mode 100644
index 00000000000..dc3b61849ea
--- /dev/null
+++ b/build_files/cmake/have_features.cmake
@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2022 Blender Foundation. All rights reserved.
+
+# This file is used to test the system for headers & symbols.
+# Variables should use the `HAVE_` prefix.
+# Defines should use the same name as the CMAKE variable.
+
+include(CheckSymbolExists)
+
+# Used for: `intern/guardedalloc/intern/mallocn_intern.h`.
+# Function `malloc_stats` is only available on GLIBC,
+# so check that before defining `HAVE_MALLOC_STATS`.
+check_symbol_exists(malloc_stats "malloc.h" HAVE_MALLOC_STATS_H)
+
+# Used for: `source/creator/creator_signals.c`.
+# The function `feenableexcept` is not present non-GLIBC systems,
+# hence we need to check if it's available in the `fenv.h` file.
+set(HAVE_FEENABLEEXCEPT OFF)
+if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+  check_symbol_exists(feenableexcept "fenv.h" HAVE_FEENABLEEXCEPT)
+endif()
+
+# Used for: `source/blender/blenlib/intern/system.c`.
+# `execinfo` is not available on non-GLIBC systems (at least not on MUSL-LIBC),
+# so check the presence of the header before including it and  using the it for back-trace.
+set(HAVE_EXECINFO_H OFF)
+if(NOT MSVC)
+  include(CheckIncludeFiles)
+  check_include_files("execinfo.h" HAVE_EXECINFO_H)
+  if(HAVE_EXECINFO_H)
+    add_definitions(-DHAVE_EXECINFO_H)
+  endif()
+endif()