Fix a bunch of compiler warnings, particularly for old compilers

Works now much better with old C99 and C++98 standard compilers.
Fixed: C++ comments in C files and headers included by C files.

There are still some warnings with C90 though but these would be
hard to fix and left as-is for now.

test/fractals.cxx: some arrays were too small by 1, or the compiler
  warned at least (false positive?). Anyway, it's fixed now.

1 files changed, 0 insertions, 1 deletions

diff --git a/src/numericsort.c b/src/numericsort.c
index bf73bb927..244f0334d 100644
--- a/src/numericsort.c
+++ b/src/numericsort.c
@@ -73,7 +73,6 @@ static int numericsort(struct dirent **A, struct dirent **B, int cs) {
       }
 
       if (a >= end_a) break;
-      //a++; b++;
     }
   }
   if (!ret) return 0;