Fix compilation with old (4.1) GCC and libstdc++

We use GCC version <= 4.1 as the criterion for the fix (which is the
same as the similar Solaris fix).  Probably we could use __GLIBCXX__
and/or __GLIBCPP__ to detect this better, but I haven't been able
to test that (in particular, old g++ with a different libstdc++).

This reverts commit 0e1e71dfe8e254a2d925fcb0a7ee6905c4175dd1.  We still
have to do some kind of casting for that particular case, though,
because the first argument is unsigned.

1 files changed, 9 insertions, 4 deletions

diff --git a/crawl-ref/source/AppHdr.h b/crawl-ref/source/AppHdr.h
index 5c2b613978..d73d2a1adc 100644
--- a/crawl-ref/source/AppHdr.h
+++ b/crawl-ref/source/AppHdr.h
@@ -45,10 +45,15 @@ static inline T move(T x) { return x; } // good enough for our purposes
 #define ENUM_INT64
 #endif
 
-#ifdef __sun
-// Solaris libc has ambiguous overloads for float, double, long float, so
-// we need to upgrade ints explicitely:
-#include <math.h>
+#if defined(__sun) || defined(__GNUC__) \
+                      && __GNUC__ * 100 + __GNUC_MINOR__ <= 401
+// Solaris libc and older GNU libstdc++ have ambiguous overloads for
+// float, double, long float, so we need to upgrade ints explicitely.
+# ifndef __sun
+#  include <cmath>
+# else
+#  include <math.h> // XXX: Does Solaris really need this and not <cmath>?
+# endif
 static inline double sqrt(int x) { return sqrt((double)x); }
 static inline double atan2(int x, int y) { return atan2((double)x, (double)y); }
 static inline double pow(int x, int y) { return std::pow((double)x, y); }