Add -fno-strict-aliasing workaround for Linux GCC targets

Most Linux distros work around aliasing problems in Mesa by compiling
with the GCC option -fno-strict-aliasing. Two examples:

  https://bugs.freedesktop.org/show_bug.cgi?id=6046
  http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=394311

This makes -fno-strict-aliasing the default with a comment that
developers should consider commenting it out. There is a already a note
about these bugs in docs/helpwanted.html.
diff --git a/configs/linux-x86-glide b/configs/linux-x86-glide
index f2f8aee..941efc1 100644
--- a/configs/linux-x86-glide
+++ b/configs/linux-x86-glide
@@ -14,6 +14,9 @@
 
 GLUT_CFLAGS = -fexceptions
 
+# Work around aliasing bugs - developers should comment this out
+CFLAGS += -fno-strict-aliasing
+CXXFLAGS += -fno-strict-aliasing
 
 ASM_SOURCES = $(X86_SOURCES)
 ASM_API = $(X86_API)