Recommit r193732:

Remove __gnu89_inline.

  Now that we use C99 almost everywhere, just use C99-style in the pmap
  code. Since the pmap code is the only consumer of __gnu89_inline, remove
  it from cdefs.h as well. Because the flag was only introduced 17 months
  ago, I don't expect any problems.

  Reviewed by:    alc

It was backed out, because it prevented us from building kernels using a
7.x compiler. Now that most people use 8.x, there is nothing that holds
us back. Even if people run 7.x, they should be able to build a kernel
if they run `make kernel-toolchain' or `make buildworld' first.

Makefile

@@ -303,7 +303,7 @@ universe_${target}:
 .if !defined(MAKE_JUST_KERNELS)
 	@echo ">> ${target} started on `LC_ALL=C date`"
 	@(cd ${.CURDIR} && env __MAKE_CONF=/dev/null \
-	    ${MAKE} ${JFLAG} buildworld \
+	    ${MAKE} ${JFLAG} kernel-toolchain \
 	    TARGET=${target} \
 	    > _.${target}.buildworld 2>&1 || \
 	    (echo "${target} world failed," \

sys/amd64/amd64/pmap.c

@@ -153,7 +153,7 @@ __FBSDID("$FreeBSD$");
 #endif
 
 #if !defined(DIAGNOSTIC)
-#define PMAP_INLINE	__gnu89_inline
+#define PMAP_INLINE	extern inline
 #else
 #define PMAP_INLINE
 #endif

sys/i386/i386/pmap.c

@@ -162,7 +162,7 @@ __FBSDID("$FreeBSD$");
 #endif
 
 #if !defined(DIAGNOSTIC)
-#define PMAP_INLINE	__gnu89_inline
+#define PMAP_INLINE	extern inline
 #else
 #define PMAP_INLINE
 #endif

sys/i386/xen/pmap.c

@@ -173,7 +173,7 @@ __FBSDID("$FreeBSD$");
 #endif
 
 #if !defined(PMAP_DIAGNOSTIC)
-#define PMAP_INLINE	__gnu89_inline
+#define PMAP_INLINE	extern inline
 #else
 #define PMAP_INLINE
 #endif

sys/sys/cdefs.h

@@ -234,12 +234,6 @@
 #define	__always_inline
 #endif
 
-#if __GNUC_PREREQ__(4, 2) /* actually 4.1.3 */
-#define	__gnu89_inline	__attribute__((__gnu_inline__)) __inline
-#else
-#define	__gnu89_inline
-#endif
-
 #if __GNUC_PREREQ__(3, 1)
 #define	__noinline	__attribute__ ((__noinline__))
 #else