Updated with AC_LANG_SOURCE directives

Please see this informative thread on bug-autoconf:
http://www.mail-archive.com/bug-autoconf@gnu.org/msg03052.html

scripts/attributes.m4

@@ -3,10 +3,10 @@
 AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [
 	AC_CACHE_CHECK([if compiler supports __attribute__((constructor))],
 		[cc_cv_attribute_constructor],
-		[AC_COMPILE_IFELSE([
+		[AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 			void ctor() __attribute__((constructor));
 			void ctor() { };
-			],
+			])],
 			[cc_cv_attribute_constructor=yes],
 			[cc_cv_attribute_constructor=no])
 		])
@@ -23,9 +23,9 @@ AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [
 AC_DEFUN([CC_ATTRIBUTE_FORMAT], [
 	AC_CACHE_CHECK([if compiler supports __attribute__((format(printf, n, n)))],
 		[cc_cv_attribute_format],
-		[AC_COMPILE_IFELSE([
+		[AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 			void __attribute__((format(printf, 1, 2))) printflike(const char *fmt, ...) { }
-			],
+			])],
 			[cc_cv_attribute_format=yes],
 			[cc_cv_attribute_format=no])
 		])
@@ -42,9 +42,9 @@ AC_DEFUN([CC_ATTRIBUTE_FORMAT], [
 AC_DEFUN([CC_ATTRIBUTE_INTERNAL], [
 	AC_CACHE_CHECK([if compiler supports __attribute__((visibility("internal")))],
 		[cc_cv_attribute_internal],
-		[AC_COMPILE_IFELSE([
+		[AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 			void __attribute__((visibility("internal"))) internal_function() { }
-			],
+			])],
 			[cc_cv_attribute_internal=yes],
 			[cc_cv_attribute_internal=no])
 		])
@@ -66,9 +66,9 @@ AC_DEFUN([CC_ATTRIBUTE_VISIBILITY], [
 
 	AC_CACHE_CHECK([if compiler supports __attribute__((visibility("default")))],
 		[cc_cv_attribute_visibility],
-		[AC_COMPILE_IFELSE([
+		[AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 			void __attribute__((visibility("default"))) visibility_function() { }
-			],
+			])],
 			[cc_cv_attribute_visibility=yes],
 			[cc_cv_attribute_visibility=no])
 		])
@@ -90,10 +90,10 @@ AC_DEFUN([CC_ATTRIBUTE_VISIBILITY], [
 AC_DEFUN([CC_ATTRIBUTE_NONNULL], [
 	AC_CACHE_CHECK([if compiler supports __attribute__((nonnull()))],
 		[cc_cv_attribute_nonnull],
-		[AC_COMPILE_IFELSE([
+		[AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 			void some_function(void *foo, void *bar) __attribute__((nonnull()));
 			void some_function(void *foo, void *bar) { }
-			],
+			])],
 			[cc_cv_attribute_nonnull=yes],
 			[cc_cv_attribute_nonnull=no])
 		])
@@ -110,9 +110,9 @@ AC_DEFUN([CC_ATTRIBUTE_NONNULL], [
 AC_DEFUN([CC_ATTRIBUTE_UNUSED], [
 	AC_CACHE_CHECK([if compiler supports __attribute__((unused))],
 		[cc_cv_attribute_unused],
-		[AC_COMPILE_IFELSE([
+		[AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 			void some_function(void *foo, __attribute__((unused)) void *bar);
-			],
+			])],
 			[cc_cv_attribute_unused=yes],
 			[cc_cv_attribute_unused=no])
 		])
@@ -129,13 +129,13 @@ AC_DEFUN([CC_ATTRIBUTE_UNUSED], [
 AC_DEFUN([CC_FUNC_EXPECT], [
 	AC_CACHE_CHECK([if compiler has __builtin_expect function],
 		[cc_cv_func_expect],
-		[AC_COMPILE_IFELSE([
+		[AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 			int some_function()
 			{
 				int a = 3;
 				return (int)__builtin_expect(a, 3);
 			}
-			],
+			])],
 			[cc_cv_func_expect=yes],
 			[cc_cv_func_expect=no])
 		])

scripts/checks.m4

@@ -1,15 +1,15 @@
 AC_DEFUN([TORRENT_CHECK_XFS], [
   AC_MSG_CHECKING(for XFS support)
 
-  AC_COMPILE_IFELSE(
-    [[#include <xfs/libxfs.h>
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+      #include <xfs/libxfs.h>
       #include <sys/ioctl.h>
       int main() {
         struct xfs_flock64 l;
         ioctl(0, XFS_IOC_RESVSP64, &l);
         return 0;
       }
-    ]],
+      ])],
     [
       AC_DEFINE(USE_XFS, 1, Use XFS filesystem stuff.)
       AC_MSG_RESULT(yes)
@@ -46,13 +46,13 @@ AC_DEFUN([TORRENT_WITH_XFS], [
 AC_DEFUN([TORRENT_CHECK_EPOLL], [
   AC_MSG_CHECKING(for epoll support)
 
-  AC_COMPILE_IFELSE(
-    [[#include <sys/epoll.h>
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+      #include <sys/epoll.h>
       int main() {
         int fd = epoll_create(100);
         return 0;
       }
-    ]],
+      ])],
     [
       AC_DEFINE(USE_EPOLL, 1, Use epoll.)
       AC_MSG_RESULT(yes)
@@ -77,14 +77,14 @@ AC_DEFUN([TORRENT_WITHOUT_EPOLL], [
 AC_DEFUN([TORRENT_CHECK_KQUEUE], [
   AC_MSG_CHECKING(for kqueue support)
 
-  AC_LINK_IFELSE(
-    [[#include <sys/time.h>  /* Because OpenBSD's sys/event.h fails to compile otherwise. Yeah... */
+  AC_LINK_IFELSE([AC_LANG_SOURCE([
+      #include <sys/time.h>  /* Because OpenBSD's sys/event.h fails to compile otherwise. Yeah... */
       #include <sys/event.h>
       int main() {
         int fd = kqueue();
         return 0;
       }
-    ]],
+      ])],
     [
       AC_DEFINE(USE_KQUEUE, 1, Use kqueue.)
       AC_MSG_RESULT(yes)
@@ -96,8 +96,8 @@ AC_DEFUN([TORRENT_CHECK_KQUEUE], [
 AC_DEFUN([TORRENT_CHECK_KQUEUE_SOCKET_ONLY], [
   AC_MSG_CHECKING(whether kqueue supports pipes and ptys)
 
-  AC_RUN_IFELSE(
-    [[#include <fcntl.h>
+  AC_RUN_IFELSE([AC_LANG_SOURCE([
+      #include <fcntl.h>
       #include <stdlib.h>
       #include <unistd.h>
       #include <sys/event.h>
@@ -122,7 +122,7 @@ AC_DEFUN([TORRENT_CHECK_KQUEUE_SOCKET_ONLY], [
         if ((n = kevent(kfd, NULL, 0, ev_out, 2, &ts)) < 1) return 9;
         return 0;
       }
-    ]],
+      ])],
     [
       AC_MSG_RESULT(yes)
     ], [
@@ -364,11 +364,11 @@ AC_DEFUN([TORRENT_CHECK_TR1], [
   AC_LANG_PUSH(C++)
   AC_MSG_CHECKING(for TR1 support)
 
-  AC_COMPILE_IFELSE(
-    [[#include <tr1/unordered_map>
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+      #include <tr1/unordered_map>
       class Foo;
       typedef std::tr1::unordered_map<Foo*, int> Bar;
-    ]],
+      ])],
     [
       AC_MSG_RESULT(yes)
       AC_DEFINE(HAVE_TR1, 1, Define to 1 if your C++ library supports the extensions from Technical Report 1)
@@ -385,14 +385,14 @@ AC_DEFUN([TORRENT_CHECK_CXX11], [
   AC_LANG_PUSH(C++)
   AC_MSG_CHECKING(for C++11 support)
 
-  AC_COMPILE_IFELSE(
-    [[#include <functional>
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+      #include <functional>
       #include <unordered_map>
       class Foo;
       typedef std::unordered_map<Foo*, int> Bar;
 
       union test { Bar b1; };
-    ]],
+      ])],
     [
       AC_MSG_RESULT(yes)
       AC_DEFINE(HAVE_CXX11, 1, Define to 1 if your C++ compiler has support for C++11.)

scripts/common.m4

@@ -99,11 +99,11 @@ AC_DEFUN([TORRENT_OTFD], [
   AC_LANG_PUSH(C++)
   AC_MSG_CHECKING(for proper overloaded template function disambiguation)
 
-  AC_COMPILE_IFELSE(
-    [[template <typename T> void f(T&) {}
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+      template <typename T> void f(T&) {}
       template <typename T> void f(T*) {}
       int main() { int *i = 0; f(*i); f(i); }
-    ]],
+      ])],
     [
       AC_MSG_RESULT(yes)
     ], [
@@ -119,24 +119,24 @@ AC_DEFUN([TORRENT_MINCORE_SIGNEDNESS], [
   AC_LANG_PUSH(C++)
   AC_MSG_CHECKING(signedness of mincore parameter)
 
-  AC_COMPILE_IFELSE(
-    [[#include <sys/types.h>
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+      #include <sys/types.h>
       #include <sys/mman.h>
       #include <unistd.h>
       void f() { mincore((char*)0, 0, (unsigned char*)0); }
-    ]],
+      ])],
     [
       AC_DEFINE(USE_MINCORE, 1, Use mincore)
       AC_DEFINE(USE_MINCORE_UNSIGNED, 1, use unsigned char* in mincore)
       AC_MSG_RESULT(unsigned)
     ],
     [
-      AC_COMPILE_IFELSE(
-        [[#include <sys/types.h>
+      AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+          #include <sys/types.h>
           #include <sys/mman.h>
           #include <unistd.h>
           void f() { mincore((char*)0, 0, (char*)0); }
-        ]],
+          ])],
         [
           AC_DEFINE(USE_MINCORE, 1, Use mincore)
           AC_DEFINE(USE_MINCORE_UNSIGNED, 0, use char* in mincore)
@@ -168,11 +168,11 @@ AC_DEFUN([TORRENT_MINCORE], [
 AC_DEFUN([TORRENT_CHECK_MADVISE], [
   AC_MSG_CHECKING(for madvise)
 
-  AC_COMPILE_IFELSE(
-    [[#include <sys/types.h>
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+      #include <sys/types.h>
           #include <sys/mman.h>
           void f() { static char test[1024]; madvise((void *)test, sizeof(test), MADV_NORMAL); }
-    ]],
+      ])],
     [
       AC_MSG_RESULT(yes)
       AC_DEFINE(USE_MADVISE, 1, Use madvise)
@@ -184,10 +184,9 @@ AC_DEFUN([TORRENT_CHECK_MADVISE], [
 AC_DEFUN([TORRENT_CHECK_POPCOUNT], [
   AC_MSG_CHECKING(for __builtin_popcount)
 
-  AC_COMPILE_IFELSE(
-    [[
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([
       void f() { __builtin_popcount(0); }
-    ]],
+    ])],
     [
       AC_MSG_RESULT(yes)
       AC_DEFINE(USE_BUILTIN_POPCOUNT, 1, Use __builtin_popcount.)
@@ -199,12 +198,12 @@ AC_DEFUN([TORRENT_CHECK_POPCOUNT], [
 AC_DEFUN([TORRENT_CHECK_CACHELINE], [
   AC_MSG_CHECKING(for cacheline)
 
-  AC_COMPILE_IFELSE(
-    [[#include <stdlib.h>
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+      #include <stdlib.h>
           #include <linux/cache.h>
           void* vptr __cacheline_aligned;
           void f() { posix_memalign(&vptr, SMP_CACHE_BYTES, 42); }
-    ]],
+      ])],
     [
       AC_MSG_RESULT(found builtin)
 dnl      AC_DEFINE(LT_SMP_CACHE_BYTES, SMP_CACHE_BYTES, Largest L1 cache size we know of, should work on all archs.)
@@ -224,10 +223,10 @@ dnl   Need to fix this so that it uses the stuff defined by the system.
 AC_DEFUN([TORRENT_CHECK_EXECINFO], [
   AC_MSG_CHECKING(for execinfo.h)
 
-  AC_RUN_IFELSE(
-    [[#include <execinfo.h>
+  AC_RUN_IFELSE([AC_LANG_SOURCE([
+      #include <execinfo.h>
       int main() { backtrace((void**)0, 0); backtrace_symbols((char**)0, 0); return 0;}
-    ]],
+      ])],
     [
       AC_MSG_RESULT(yes)
       AC_DEFINE(USE_EXECINFO, 1, Use execinfo.h)
@@ -239,8 +238,8 @@ AC_DEFUN([TORRENT_CHECK_EXECINFO], [
 AC_DEFUN([TORRENT_CHECK_ALIGNED], [
   AC_MSG_CHECKING(the byte alignment)
 
-  AC_RUN_IFELSE(
-    [[#include <inttypes.h>
+  AC_RUN_IFELSE([AC_LANG_SOURCE([
+      #include <inttypes.h>
       int main() {
         char buf[8] = { 0, 0, 0, 0, 1, 0, 0, 0 };
 	int i;
@@ -248,7 +247,7 @@ AC_DEFUN([TORRENT_CHECK_ALIGNED], [
 	  if (*(uint32_t*)(buf + i) == 0) return -1;
 	return 0;
 	}
-    ]],
+      ])],
     [
       AC_MSG_RESULT(none needed)
     ], [