Add support for 2-digit zlib version like "1.3".
--- a/src/acinclude.m4
+++ b/src/acinclude.m4
@@ -67,7 +67,7 @@ char* my_strdup (char *str)
 
 int main (int argc, char *argv[])
 {
-  int major, minor, micro, zlib_major_version, zlib_minor_version, zlib_micro_version;
+  int major, minor, micro, zlib_major_version, zlib_minor_version, zlib_micro_version = 0;
 
   char *zlibver, *tmp_version;
 
@@ -85,7 +85,7 @@ int main (int argc, char *argv[])
     printf("%s, bad version string for\n\tmin_zlib_version... ", "$min_zlib_version");
     exit(1);
   }
-  if (sscanf(zlibver, "%d.%d.%d", &zlib_major_version, &zlib_minor_version, &zlib_micro_version) != 3) {
+  if (sscanf(zlibver, "%d.%d.%d", &zlib_major_version, &zlib_minor_version, &zlib_micro_version) != 3 && sscanf(zlibver, "%d.%d", &zlib_major_version, &zlib_minor_version) != 2) {
     printf("%s, bad version string given\n", zlibver);
     puts("\tby zlib, sometimes due to very old zlibs that didnt correctly");
     printf("\tdefine their version. Please upgrade if you are running an\n\told zlib... ");
--- a/src/configure
+++ b/src/configure
@@ -3817,7 +3817,7 @@ char* my_strdup (char *str)
 
 int main (int argc, char *argv[])
 {
-  int major, minor, micro, zlib_major_version, zlib_minor_version, zlib_micro_version;
+  int major, minor, micro, zlib_major_version, zlib_minor_version, zlib_micro_version = 0;
 
   char *zlibver, *tmp_version;
 
@@ -3835,7 +3835,7 @@ int main (int argc, char *argv[])
     printf("%s, bad version string for\n\tmin_zlib_version... ", "$min_zlib_version");
     exit(1);
   }
-  if (sscanf(zlibver, "%d.%d.%d", &zlib_major_version, &zlib_minor_version, &zlib_micro_version) != 3) {
+  if (sscanf(zlibver, "%d.%d.%d", &zlib_major_version, &zlib_minor_version, &zlib_micro_version) != 3 && sscanf(zlibver, "%d.%d", &zlib_major_version, &zlib_minor_version) != 2) {
     printf("%s, bad version string given\n", zlibver);
     puts("\tby zlib, sometimes due to very old zlibs that didnt correctly");
     printf("\tdefine their version. Please upgrade if you are running an\n\told zlib... ");