Links with -lm if fmin doesn't seem to be a builtin

1 files changed, 12 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 663aaef..65d3671 100644
--- a/configure.ac
+++ b/configure.ac
@@ -79,6 +79,14 @@ case ${host_os} in
 esac
 AM_CONDITIONAL(WIN32, test x$win32 = xtrue)
 
+# Check if we need libm for fmin
+AC_CACHE_CHECK(if fmin is a builtin function, ac_cv_fmin_builtin,
+        AC_TRY_COMPILE([
+                #include <math.h>
+        ], [
+                fmin(0.1f, 0.2f);
+        ], ac_cv_fmin_builtin=yes, ac_cv_fmin_builtin=no))
+
 # Check if struct tm has a tm_gmtoff member
 AC_CACHE_CHECK(for tm_gmtoff in struct tm, ac_cv_struct_tm_gmtoff,
         AC_TRY_COMPILE([
@@ -139,6 +147,10 @@ AM_CONDITIONAL([HAVE_CYTHON],[test "x$cython_python_bindings" = "xyes"])
 AS_COMPILER_FLAGS(GLOBAL_CFLAGS, "-Wall -Wextra -Wredundant-decls -Wshadow -Wpointer-arith  -Wwrite-strings -Wswitch-default -Wno-unused-parameter -Wno-strict-aliasing -fvisibility=hidden $PTHREAD_CFLAGS")
 GLOBAL_LDFLAGS="$PTHREAD_LIBS"
 
+if test "x$ac_cv_fmin_builtin" != "xyes"; then
+        GLOBAL_LDFLAGS+=" -lm"
+fi
+
 AC_ARG_ENABLE(debug,
 AS_HELP_STRING([--enable-debug],
                [enable debugging, default: no]),