Config changes

Author: StanFromIreland

configure

@@ -5323,36 +5323,35 @@ if test "$ac_cv_have_lchflags" = yes ; then
 fi
 
 dnl Check for compression libraries
-AH_TEMPLATE([HAVE_ZLIB_COPY], [Define if the zlib library has inflateCopy])
-
-dnl detect zlib from Emscripten emport
-PY_CHECK_EMSCRIPTEN_PORT([ZLIB], [-sUSE_ZLIB])
+AH_TEMPLATE([HAVE_ZLIB_COPY], [Define if the zlib library has inflateCopy; zlib 1.2.0 (2003) added inflateCopy.])
+dnl 2022-03: Until we know if third party zlib modules people use (for hardware
+dnl accelerators, parallelism, etc.) all support copy, lets not assume.
 
 PKG_CHECK_MODULES([ZLIB], [zlib >= 1.2.0], [
-  have_zlib=yes
   dnl zlib 1.2.0 (2003) added inflateCopy
   AC_DEFINE([HAVE_ZLIB_COPY], [1])
 ], [
-  WITH_SAVE_ENV([
-    CPPFLAGS="$CPPFLAGS $ZLIB_CFLAGS"
-    LIBS="$LIBS $ZLIB_LIBS"
-    AC_CHECK_HEADERS([zlib.h], [
-      PY_CHECK_LIB([z], [gzread], [have_zlib=yes], [have_zlib=no])
-    ], [have_zlib=no])
-    AS_VAR_IF([have_zlib], [yes], [
-      ZLIB_CFLAGS=${ZLIB_CFLAGS-""}
-      ZLIB_LIBS=${ZLIB_LIBS-"-lz"}
-      PY_CHECK_LIB([z], [inflateCopy], [AC_DEFINE([HAVE_ZLIB_COPY], [1])])
+  AC_CHECK_HEADERS([zlib.h], [
+    WITH_SAVE_ENV([
+      AC_CHECK_LIB([z], [gzread], [
+        ZLIB_CFLAGS=${ZLIB_CFLAGS-""}
+        ZLIB_LIBS=${ZLIB_LIBS-"-lz"}
+        AC_CHECK_LIB([z], [inflateCopy], [AC_DEFINE([HAVE_ZLIB_COPY], [1])])
+      ], [
+        AC_MSG_ERROR([m4_normalize([
+          zlib.h and libz are required. Install your OS's zlib-devel or
+          zlib1g-dev equivalent library or get it from https://zlib.net/.
+        ])])
+      ])
     ])
+    ], [
+      AC_MSG_ERROR([m4_normalize([
+        zlib.h and libz are required. Install your OS's zlib-devel or
+        zlib1g-dev equivalent library or get it from https://zlib.net/.
+     ])])
   ])
 ])
 
-dnl binascii can use zlib for optimized crc32.
-AS_VAR_IF([have_zlib], [yes], [
-  BINASCII_CFLAGS="-DUSE_ZLIB_CRC32 $ZLIB_CFLAGS"
-  BINASCII_LIBS="$ZLIB_LIBS"
-])
-
 dnl detect bzip2 from Emscripten emport
 PY_CHECK_EMSCRIPTEN_PORT([BZIP2], [-sUSE_BZIP2])
 
@@ -7933,10 +7932,9 @@ PY_STDLIB_MOD([_uuid],
   [$LIBUUID_CFLAGS], [$LIBUUID_LIBS])
 
 dnl compression libs
-PY_STDLIB_MOD([zlib], [], [test "$have_zlib" = yes],
-  [$ZLIB_CFLAGS], [$ZLIB_LIBS])
-dnl binascii can use zlib for optimized crc32.
-PY_STDLIB_MOD_SIMPLE([binascii], [$BINASCII_CFLAGS], [$BINASCII_LIBS])
+PY_STDLIB_MOD_SIMPLE([zlib], [$ZLIB_CFLAGS], [$ZLIB_LIBS])
+dnl binascii uses zlib for optimized crc32.
+PY_STDLIB_MOD_SIMPLE([binascii], [$ZLIB_CFLAGS], [$ZLIB_LIBS])
 PY_STDLIB_MOD([_bz2], [], [test "$have_bzip2" = yes],
   [$BZIP2_CFLAGS], [$BZIP2_LIBS])
 PY_STDLIB_MOD([_lzma], [], [test "$have_liblzma" = yes],

configure.ac

@@ -1609,7 +1609,8 @@
 /* Define to 1 if you have the 'writev' function. */
 #undef HAVE_WRITEV
 
-/* Define if the zlib library has inflateCopy */
+/* Define if the zlib library has inflateCopy; zlib 1.2.0 (2003) added
+   inflateCopy. */
 #undef HAVE_ZLIB_COPY
 
 /* Define to 1 if you have the <zlib.h> header file. */