Remove -no-cpp-precomp compiler flag for OS X.
Remove the -no-cpp-precomp compiler flag when compiling on OS X. clang
does not support the flag, and gcc works fine without it.
diff --git a/configure.ac b/configure.ac
index 44ff6ee..e1a399b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -208,7 +208,7 @@
dnl to make happen otherwise.
case "${host}" in
*-*-darwin*)
- CFLAGS="$CFLAGS -fno-common -no-cpp-precomp"
+ CFLAGS="$CFLAGS -fno-common"
abi="macho"
AC_DEFINE([JEMALLOC_PURGE_MADVISE_FREE], [ ])
RPATH=""