Include "pm.h" for the declaration of the overflow_add function.  This
avoids an implicit function declaration.  Future C compilers will
require that all functions are declared explicitly.  Implicit function
declarations are a language feature that was removed in 1999.

Likewise, include "pm.h" for the newly added declarations of realloc2.
This fixes a pointer truncation bug in pjtoppm.

Both issues are specific to downstream patches.

diff --git a/converter/pbm/pbmtoppa/pbm.c b/converter/pbm/pbmtoppa/pbm.c
index 1c8d236219b297e1..d63cab63b13f2051 100644
--- a/converter/pbm/pbmtoppa/pbm.c
+++ b/converter/pbm/pbmtoppa/pbm.c
@@ -12,6 +12,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "pm.h"
 #include "ppapbm.h"
 
 int make_pbm_stat(pbm_stat* pbm,FILE* fptr)
diff --git a/converter/ppm/pjtoppm.c b/converter/ppm/pjtoppm.c
index c458c06457c2b9bd..5e93a6acb8d6f198 100644
--- a/converter/ppm/pjtoppm.c
+++ b/converter/ppm/pjtoppm.c
@@ -10,6 +10,7 @@
 ** implied warranty.
 */
 
+#include "pm.h"
 #include "ppm.h"
 #include "mallocvar.h"
 
diff --git a/lib/pm.h b/lib/pm.h
index 5037c2519c565fbc..435445d5e7f52fbf 100644
--- a/lib/pm.h
+++ b/lib/pm.h
@@ -457,6 +457,7 @@ pm_parse_height(const char * const arg);
 
 void *malloc2(int, int);
 void *malloc3(int, int, int);
+void *realloc2(void * a, int b, int c);
 #define overflow2(a,b) __overflow2(a,b)
 void __overflow2(int, int);
 void overflow3(int, int, int);