configure: Provide a safe default for unknonw libcs

Support musl out of box.

Amend commit 9d2cee52d37c7340f85a5d41110282aac03e6855 that got
wrongly merged in its stead.

1 files changed, 2 insertions, 2 deletions

diff --git a/configure b/configure
index 6125bcbc32..4513579c2b 100755
--- a/configure
+++ b/configure
@@ -3658,8 +3658,8 @@ probe_libc(){
         eval ${pfx}libc_type=solaris
         add_${pfx}cppflags -D__EXTENSIONS__ -D_XOPEN_SOURCE=600
     else
-        eval ${pfx}libc_type=unknown
-        add_${pfx}cppflags -D_POSIX_C_SOURCE=200112 -D_XOPEN_SOURCE=600
+        eval ${pfx}libc_type=default
+        add_${pfx}cppflags -D_DEFAULT_SOURCE
     fi
 }