Patch to solve issue with compiling GCC4.4.7 with GCC5

From b08c89d503fe6fc5c3faf5cb896a4e6bcd837a4f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
Date: Tue, 15 Sep 2015 10:57:48 +0200
Subject: [PATCH] Avoid floor_log2() redefinition with C99
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GCC 5.1 defaults to gnu11 which forbirs redefinitions. This patch
comes from <https://gcc.gnu.org/ml/gcc-patches/2009-06/msg01249.html>.

<https://github.com/gccxml/gccxml/issues/11>

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 GCC/gcc/toplev.c | 4 ++--
 GCC/gcc/toplev.h | 7 ++++---
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/GCC/gcc/toplev.c b/GCC/gcc/toplev.c
index 3526010..419dc00 100644
--- a/GCC/gcc/toplev.c
+++ b/GCC/gcc/toplev.c
@@ -537,7 +537,7 @@ read_integral_parameter (const char *p, const char *pname, const int  defval)
    for floor_log2 and exact_log2; see toplev.h.  That construct, however,
    conflicts with the ISO C++ One Definition Rule.   */

-#if GCC_VERSION < 3004 || !defined (__cplusplus)
+#if GCC_VERSION < 3004

 /* Given X, an unsigned number, return the largest int Y such that 2**Y <= X.
    If X is 0, return -1.  */
@@ -589,7 +589,7 @@ exact_log2 (unsigned HOST_WIDE_INT x)
 #endif
 }

-#endif /*  GCC_VERSION < 3004 || !defined (__cplusplus)  */
+#endif /*  GCC_VERSION < 3004 */

 /* Handler for fatal signals, such as SIGSEGV.  These are transformed
    into ICE messages, which is much more user friendly.  In case the
diff --git a/GCC/gcc/toplev.h b/GCC/gcc/toplev.h
index c935f7e..1edd5e5 100644
--- a/GCC/gcc/toplev.h
+++ b/GCC/gcc/toplev.h
@@ -151,6 +151,7 @@ extern void decode_d_option     (const char *);
 /* Return true iff flags are set as if -ffast-math.  */
 extern bool fast_math_flags_set_p  (void);

+#if GCC_VERSION < 3004
 /* Return log2, or -1 if not exact.  */
 extern int exact_log2                  (unsigned HOST_WIDE_INT);

@@ -158,7 +159,7 @@ extern int exact_log2                  (unsigned HOST_WIDE_INT);
 extern int floor_log2                  (unsigned HOST_WIDE_INT);

 /* Inline versions of the above for speed.  */
-#if GCC_VERSION >= 3004
+#else /* GCC_VERSION >= 3004 */
 # if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_LONG
 #  define CLZ_HWI __builtin_clzl
 #  define CTZ_HWI __builtin_ctzl
@@ -170,13 +171,13 @@ extern int floor_log2                  (unsigned HOST_WIDE_INT);
 #  define CTZ_HWI __builtin_ctz
 # endif

-extern inline int
+static inline int
 floor_log2 (unsigned HOST_WIDE_INT x)
 {
   return x ? HOST_BITS_PER_WIDE_INT - 1 - (int) CLZ_HWI (x) : -1;
 }

-extern inline int
+static inline int
 exact_log2 (unsigned HOST_WIDE_INT x)
 {
   return x == (x & -x) && x ? (int) CTZ_HWI (x) : -1;
--
2.4.3