When compiling with clang and -O2, local variable origJmpbufP with value
changed after setjmp contains garbage after longjmp.

According to glibc documentation, making it volatile should have fixed the
issue, but it didn't.  Static outside the function works.

Bug: https://bugs.gentoo.org/885561

--- a/lib/libpamread.c
+++ b/lib/libpamread.c
@@ -25,6 +25,7 @@
 #include "fileio.h"
 #include "pam.h"
 
+static jmp_buf * origJmpbufP = NULL;
 
 static void
 readPbmRow(const struct pam * const pamP,
@@ -35,7 +36,6 @@
                  "It says PBM format, but 'depth' member is not 1.");
     else {
         jmp_buf jmpbuf;
-        jmp_buf * origJmpbufP;
         unsigned char * bitrow;
 
         bitrow = (unsigned char *) pbm_allocrow(pbm_packed_bytes(pamP->width));