--- postfix-3.3.7/makedefs~	2020-02-08 13:42:07.000000000 +0100
+++ postfix-3.3.7/makedefs	2020-02-08 13:42:53.604246413 +0100
@@ -546,7 +546,7 @@ EOF
 		: ${SHLIB_ENV="LD_LIBRARY_PATH=`pwd`/lib"}
 		: ${PLUGIN_LD="${CC-gcc} -shared"}
 		;;
-  Linux.[34].*)	SYSTYPE=LINUX$RELEASE_MAJOR
+  Linux.[3456].*)	SYSTYPE=LINUX$RELEASE_MAJOR
 		case "$CCARGS" in
 		 *-DNO_DB*) ;;
 		 *-DHAS_DB*) ;;
--- postfix-3.3.7/src/util/sys_defs.h~	2020-02-08 13:43:34.000000000 +0100
+++ postfix-3.3.7/src/util/sys_defs.h	2020-02-08 13:44:42.064282215 +0100
@@ -748,7 +748,7 @@ extern int initgroups(const char *, int)
  /*
   * LINUX.
   */
-#if defined(LINUX2) || defined(LINUX3) || defined(LINUX4)
+#if defined(LINUX2) || defined(LINUX3) || defined(LINUX4) || defined(LINUX5) || defined(LINUX6)
 #define SUPPORTED
 #define UINT32_TYPE	unsigned int
 #define UINT16_TYPE	unsigned short