libctf: compilation failure on MinGW due to missing errno values

This commit fixes a compilation failure in a couple of libctf files
due to the use of EOVERFLOW and ENOTSUP, which are not defined
when compiling on MinGW.

libctf/ChangeLog:

	PR binutils/25155:
	* ctf-create.c (EOVERFLOW): If not defined by system header,
	redirect to ERANGE as a poor man's substitute.
	* ctf-subr.c (ENOTSUP): If not defined, use ENOSYS instead.

(cherry picked from commit 50500ecfefd6acc4c7f6c2a95bc0ae1945103220)

libctf/ChangeLog

@@ -1,3 +1,10 @@
+2020-07-26  Eli Zaretskii  <eliz@gnu.org>
+
+	PR binutils/25155:
+	* ctf-create.c (EOVERFLOW): If not defined by system header,
+	redirect to ERANGE as a poor man's substitute.
+	* ctf-subr.c (ENOTSUP): If not defined, use ENOSYS instead.
+
 2020-07-22  Nick Alcock  <nick.alcock@oracle.com>
 
 	* ctf-create.c (ctf_dtd_insert): Add uintptr_t casts.

libctf/ctf-create.c

@@ -24,6 +24,10 @@
 #include <unistd.h>
 #include <zlib.h>
 
+#ifndef EOVERFLOW
+#define EOVERFLOW ERANGE
+#endif
+
 #ifndef roundup
 #define roundup(x, y)  ((((x) + ((y) - 1)) / (y)) * (y))
 #endif

libctf/ctf-subr.c

@@ -26,6 +26,10 @@
 #include <string.h>
 #include <unistd.h>
 
+#ifndef ENOTSUP
+#define ENOTSUP ENOSYS
+#endif
+
 int _libctf_version = CTF_VERSION;	      /* Library client version.  */
 int _libctf_debug = 0;			      /* Debugging messages enabled.  */