Fix build on Linux kernel 5.x+

[Khem Raj]

Recognise kernel 5.x versioning scheme

Signed-off-by: Khem Raj <raj.k...@gmail.com>

--- a/makedefs
+++ b/makedefs
@@ -543,7 +543,7 @@ EOF
                : ${SHLIB_ENV="LD_LIBRARY_PATH=`pwd`/lib"}
                : ${PLUGIN_LD="${CC-gcc} -shared"}
                ;;
-  Linux.[34].*)        SYSTYPE=LINUX$RELEASE_MAJOR
+  Linux.[345].*)       SYSTYPE=LINUX$RELEASE_MAJOR
                case "$CCARGS" in
                 *-DNO_DB*) ;;
                 *-DHAS_DB*) ;;
--- a/src/util/sys_defs.h
+++ b/src/util/sys_defs.h
@@ -749,7 +749,7 @@ extern int initgroups(const char *, int)
  /*
   * LINUX.
   */
-#if defined(LINUX2) || defined(LINUX3) || defined(LINUX4)
+#if defined(LINUX2) || defined(LINUX3) || defined(LINUX4) || defined(LINUX5)
 #define SUPPORTED
 #define UINT32_TYPE    unsigned int
 #define UINT16_TYPE    unsigned short