mescc: Support glibc-2.2.5: header tweaks.

* include/sys/types.h [__PTRDIFF_T]: Extra guard for ptrdiff_t.
  [__SIZE_T]: Extra guard for size_t.
* include/stdlib.h: Include alloca; remove alloca prototype,
* include/errno.h: Add E2BIG.

include/alloca.h

@@ -28,7 +28,21 @@
 #include_next <alloca.h>
 
 #else // ! WITH_GLIBC
-void* alloca (size_t);
+
+#ifndef __MES_SIZE_T
+#define __MES_SIZE_T
+#undef size_t
+typedef unsigned long size_t;
+#endif
+
+#if _ALLOCA_UNSIGNED
+void * alloca (unsigned size);
+#elif _ALLOCA_CHAR
+char * alloca (int);
+#else
+void * alloca (size_t size);
+#endif
+
 #endif // ! WITH_GLIBC
 
 #endif // __MES_ALLOCA_H

include/errno.h

@@ -31,6 +31,7 @@ int errno;
 #define ENOENT   2
 #define EINTR    4
 #define EIO      5
+#define E2BIG    7
 #define EBADF    9
 #define EAGAIN  11
 #define ENOMEM  12

include/stddef.h

@@ -25,6 +25,13 @@
 #include_next <stddef.h>
 #else // ! WITH_GLIBC
 
+#ifndef __MES_SIZE_T
+#define __MES_SIZE_T
+#undef size_t
+typedef unsigned long size_t;
+#endif
+
+#include <sys/types.h>
 #include <stdint.h>
 #include <unistd.h>
 

include/stdlib.h

@@ -29,12 +29,8 @@
 #else  // ! WITH_GLIBC
 
 #include <sys/types.h>
+#include <alloca.h>
 
-#if _ALLOCA_UNSIGNED
-void * alloca (unsigned size);
-#else
-void * alloca (size_t size);
-#endif
 int atoi (char const *s);
 int atexit (void (*function) (void));
 void * calloc (size_t nmemb, size_t size);

include/sys/types.h

@@ -87,11 +87,14 @@ typedef unsigned long off_t;
 typedef int pid_t;
 #endif
 
+#ifndef __PTRDIFF_T
+#define __PTRDIFF_T
 #ifndef __MES_PTRDIFF_T
 #define __MES_PTRDIFF_T
 #undef ptrdiff_t
 typedef long ptrdiff_t;
 #endif
+#endif
 
 #ifndef __MES_SIGVAL_T
 #define __MES_SIGVAL_T
@@ -99,11 +102,14 @@ typedef long ptrdiff_t;
 typedef int sigval_t;
 #endif
 
+#ifndef __SIZE_T
+#define __SIZE_T
 #ifndef __MES_SIZE_T
 #define __MES_SIZE_T
 #undef size_t
 typedef unsigned long size_t;
 #endif
+#endif
 
 #ifndef __MES_SSIZE_T
 #define __MES_SSIZE_T