From 3ff6158d857c952ea1936a6e387a20ad5b624d5a Mon Sep 17 00:00:00 2001
From: Thomas Goyne <plorkyeran@aegisub.org>
Date: Sat, 24 Nov 2012 09:05:17 -0800
Subject: [PATCH] Fix configure check for libc++

---
 aegisub/configure.ac        | 22 ++++++++++++++++++++--
 aegisub/m4macros/ac_flag.m4 | 15 ---------------
 2 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/aegisub/configure.ac b/aegisub/configure.ac
index 9b1ecd0e0..c0cbf46dd 100644
--- a/aegisub/configure.ac
+++ b/aegisub/configure.ac
@@ -168,8 +168,6 @@ AS_IF([test x$enable_compiler_flags != xno], [
   AC_CXX_FLAG([-pipe])
   AC_CXX_FLAG([-g])
   AC_CXX_FLAG([-std=c++11])
-  AC_CXX_FLAG([-stdlib=libc++])
-  AC_LD_FLAG([-stdlib=libc++])
 
   # -O* messes with debugging.
   AS_IF([test x$enable_debug = xyes], [
@@ -181,6 +179,26 @@ AS_IF([test x$enable_compiler_flags != xno], [
   ])
 ])
 
+AC_ARG_WITH([libc++], AS_HELP_STRING([--with-libc++],[Use libc++ rather than libstdc++. [auto]]))
+AS_IF([test x$with_libc__ != xno], [
+  AC_LANG_PUSH(C++)
+  ac_ld_flag_save="$LDFLAGS"
+  LDFLAGS="$LDFLAGS -stdlib=libc++"
+  AC_MSG_CHECKING([[whether $CXX supports -stdlib=libc++]])
+  AC_LINK_IFELSE([AC_LANG_PROGRAM([[]])], [
+    AC_MSG_RESULT([yes])
+    CXXFLAGS="$CXXFLAGS -stdlib=libc++"
+  ], [
+    AS_IF([test x$with_libc__ = xyes], [
+      AC_MSG_FAILURE([no])
+    ], [
+      LDFLAGS="$ac_ld_flag_save"
+      AC_MSG_RESULT([no])
+    ])
+  ])
+  AC_LANG_POP(C++)
+])
+
 ######################################
 # Check Headers / Features / Libraries
 ######################################
diff --git a/aegisub/m4macros/ac_flag.m4 b/aegisub/m4macros/ac_flag.m4
index f60e65d02..cf3248a4e 100644
--- a/aegisub/m4macros/ac_flag.m4
+++ b/aegisub/m4macros/ac_flag.m4
@@ -28,21 +28,6 @@ AC_DEFUN([AC_CXX_FLAG], [{
 		])
 	AC_LANG_POP(C++)
 	}])
-AC_DEFUN([AC_LD_FLAG], [{
-	AC_LANG_PUSH(C++)
-	ac_ld_flag_save="$LDFLAGS"
-	LDFLAGS="$LDFLAGS $1"
-	AC_MSG_CHECKING([[whether $CXX supports $1]])
-	AC_LINK_IFELSE(
-		[AC_LANG_PROGRAM([[]])],
-		[AC_MSG_RESULT([yes])],
-		[
-			LDFLAGS="$ac_ld_flag_save"
-			AC_MSG_RESULT([no])
-			$2
-		])
-	AC_LANG_POP(C++)
-	}])
 AC_DEFUN([AC_PCH_FLAG], [{
 	AC_LANG_PUSH(C++)
 	ac_cxx_flag_save="$CXXFLAGS"