Update ax_lua.m4

Updated ax_lua.m4 to current version from GNU Autoconf Archive's git
repository with additional patch to support OpenBSD.[1] Regenerated
``configure'' script. DOcumented changes.

---
[1] https://savannah.gnu.org/patch/index.php?8355

README.md

@@ -65,7 +65,20 @@ Install these ports:
 
 Then build:
 
-    $ env CC=clang CFLAGS=-I/usr/local/include LDFLAGS=-L/usr/local/lib LUA=/usr/local/bin/lua52 LUA_INCLUDE=-I/usr/local/include/lua52 LUA_LIB=-llua-5.2 ./configure
+    $ env CC=clang CPPFLAGS=-I/usr/local/include LDFLAGS=-L/usr/local/lib ./configure
+    $ make
+    
+#### OpenBSD
+
+Install these packages (or *ports*):
+
+* libconfig (*devel/libconfig*)
+* libexecinfo (*devel/libexecinfo*)
+* lua >= 5.2 (*lang/lua/5.2*)
+
+Then build:
+
+    $ CPPFLAGS="-I/usr/local/include" LDFLAGS="-L/usr/local/lib" ./configure
     $ make
 
 #### Other UNIX

ax_lua.m4

@@ -109,6 +109,7 @@
 #     * /usr/include/lua/X.Y
 #     * /usr/include/luaXY
 #     * /usr/local/include/luaX.Y
+#     * /usr/local/include/lua-X.Y
 #     * /usr/local/include/lua/X.Y
 #     * /usr/local/include/luaXY
 #
@@ -182,7 +183,7 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 20
+#serial 21
 
 dnl =========================================================================
 dnl AX_PROG_LUA([MINIMUM-VERSION], [TOO-BIG-VERSION],
@@ -195,7 +196,7 @@ AC_DEFUN([AX_PROG_LUA],
 
   dnl Find a Lua interpreter.
   m4_define_default([_AX_LUA_INTERPRETER_LIST],
-    [lua lua5.2 lua5.1 lua50])
+    [lua lua5.2 lua52 lua5.1 lua51 lua50])
 
   m4_if([$1], [],
   [ dnl No version check is needed. Find any Lua interpreter.
@@ -259,7 +260,7 @@ AC_DEFUN([AX_PROG_LUA],
     AC_CACHE_CHECK([for $ax_display_LUA version], [ax_cv_lua_version],
       [ ax_cv_lua_version=`$LUA -e "print(_VERSION)" | \
           sed "s|^Lua \(.*\)|\1|" | \
-          grep -o "^@<:@0-9@:>@\+\\.@<:@0-9@:>@\+"`
+          grep -E -o "^@<:@0-9@:>@+\.@<:@0-9@:>@+"`
       ])
     AS_IF([test "x$ax_cv_lua_version" = 'x'],
       [AC_MSG_ERROR([invalid Lua version number])])
@@ -364,7 +365,7 @@ dnl =========================================================================
 AC_DEFUN([_AX_LUA_CHK_VER],
 [
   _ax_test_ver=`$1 -e "print(_VERSION)" 2>/dev/null | \
-    sed "s|^Lua \(.*\)|\1|" | grep -o "^@<:@0-9@:>@\+\\.@<:@0-9@:>@\+"`
+    sed "s|^Lua \(.*\)|\1|" | grep -E -o "^@<:@0-9@:>@+\.@<:@0-9@:>@+"`
   AS_IF([test "x$_ax_test_ver" = 'x'],
     [_ax_test_ver='0'])
   AX_COMPARE_VERSION([$_ax_test_ver], [ge], [$2])
@@ -431,6 +432,7 @@ AC_DEFUN([AX_LUA_HEADERS],
       /usr/include/lua/$LUA_VERSION \
       /usr/include/lua$LUA_SHORT_VERSION \
       /usr/local/include/lua$LUA_VERSION \
+      /usr/local/include/lua-$LUA_VERSION \
       /usr/local/include/lua/$LUA_VERSION \
       /usr/local/include/lua$LUA_SHORT_VERSION \
     ])
@@ -490,7 +492,7 @@ int main(int argc, char ** argv)
             ],
             [ ax_cv_lua_header_version=`./conftest$EXEEXT p | \
                 sed "s|^Lua \(.*\)|\1|" | \
-                grep -o "^@<:@0-9@:>@\+\\.@<:@0-9@:>@\+"`
+                grep -E -o "^@<:@0-9@:>@+\.@<:@0-9@:>@+"`
             ],
             [ax_cv_lua_header_version='unknown'])
           CPPFLAGS=$_ax_lua_saved_cppflags
@@ -575,7 +577,12 @@ AC_DEFUN([AX_LUA_LIBS],
     dnl Try to find the Lua libs.
     _ax_lua_saved_libs=$LIBS
     LIBS="$LIBS $LUA_LIB"
-    AC_SEARCH_LIBS([lua_load], [lua$LUA_VERSION lua$LUA_SHORT_VERSION lua],
+    AC_SEARCH_LIBS([lua_load],
+                   [ lua$LUA_VERSION \
+                     lua$LUA_SHORT_VERSION \
+                     lua-$LUA_VERSION \
+                     lua-$LUA_SHORT_VERSION \
+                     lua],
                    [_ax_found_lua_libs='yes'],
                    [_ax_found_lua_libs='no'],
                    [$_ax_lua_extra_libs])

configure

@@ -2279,6 +2279,7 @@ ac_config_headers="$ac_config_headers config.h"
 #     * /usr/include/lua/X.Y
 #     * /usr/include/luaXY
 #     * /usr/local/include/luaX.Y
+#     * /usr/local/include/lua-X.Y
 #     * /usr/local/include/lua/X.Y
 #     * /usr/local/include/luaXY
 #
@@ -2352,7 +2353,7 @@ ac_config_headers="$ac_config_headers config.h"
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 20
+#serial 21
 
 
 
@@ -4049,7 +4050,7 @@ $as_echo "enabled" >&6; }
 
 
        if test "x$LUA" = 'x'; then :
-  for ac_prog in lua lua5.2 lua5.1 lua50
+  for ac_prog in lua lua5.2 lua52 lua5.1 lua51 lua50
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -4126,7 +4127,7 @@ if ${ax_cv_lua_version+:} false; then :
 else
    ax_cv_lua_version=`$LUA -e "print(_VERSION)" | \
           sed "s|^Lua \(.*\)|\1|" | \
-          grep -o "^[0-9]\+\\.[0-9]\+"`
+          grep -E -o "^[0-9]+\.[0-9]+"`
 
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_lua_version" >&5
@@ -4290,6 +4291,7 @@ done
       /usr/include/lua/$LUA_VERSION \
       /usr/include/lua$LUA_SHORT_VERSION \
       /usr/local/include/lua$LUA_VERSION \
+      /usr/local/include/lua-$LUA_VERSION \
       /usr/local/include/lua/$LUA_VERSION \
       /usr/local/include/lua$LUA_SHORT_VERSION \
     ; do
@@ -4363,7 +4365,7 @@ _ACEOF
 if ac_fn_c_try_run "$LINENO"; then :
    ax_cv_lua_header_version=`./conftest$EXEEXT p | \
                 sed "s|^Lua \(.*\)|\1|" | \
-                grep -o "^[0-9]\+\\.[0-9]\+"`
+                grep -E -o "^[0-9]+\.[0-9]+"`
 
 else
   ax_cv_lua_header_version='unknown'
@@ -4643,7 +4645,11 @@ return lua_load ();
   return 0;
 }
 _ACEOF
-for ac_lib in '' lua$LUA_VERSION lua$LUA_SHORT_VERSION lua; do
+for ac_lib in ''  lua$LUA_VERSION \
+                     lua$LUA_SHORT_VERSION \
+                     lua-$LUA_VERSION \
+                     lua-$LUA_SHORT_VERSION \
+                     lua; do
   if test -z "$ac_lib"; then
     ac_res="none required"
   else
@@ -4713,7 +4719,7 @@ $as_echo "enabled" >&6; }
 
 
        if test "x$LUA" = 'x'; then :
-  for ac_prog in lua lua5.2 lua5.1 lua50
+  for ac_prog in lua lua5.2 lua52 lua5.1 lua51 lua50
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -4790,7 +4796,7 @@ if ${ax_cv_lua_version+:} false; then :
 else
    ax_cv_lua_version=`$LUA -e "print(_VERSION)" | \
           sed "s|^Lua \(.*\)|\1|" | \
-          grep -o "^[0-9]\+\\.[0-9]\+"`
+          grep -E -o "^[0-9]+\.[0-9]+"`
 
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_lua_version" >&5
@@ -4954,6 +4960,7 @@ done
       /usr/include/lua/$LUA_VERSION \
       /usr/include/lua$LUA_SHORT_VERSION \
       /usr/local/include/lua$LUA_VERSION \
+      /usr/local/include/lua-$LUA_VERSION \
       /usr/local/include/lua/$LUA_VERSION \
       /usr/local/include/lua$LUA_SHORT_VERSION \
     ; do
@@ -5027,7 +5034,7 @@ _ACEOF
 if ac_fn_c_try_run "$LINENO"; then :
    ax_cv_lua_header_version=`./conftest$EXEEXT p | \
                 sed "s|^Lua \(.*\)|\1|" | \
-                grep -o "^[0-9]\+\\.[0-9]\+"`
+                grep -E -o "^[0-9]+\.[0-9]+"`
 
 else
   ax_cv_lua_header_version='unknown'
@@ -5307,7 +5314,11 @@ return lua_load ();
   return 0;
 }
 _ACEOF
-for ac_lib in '' lua$LUA_VERSION lua$LUA_SHORT_VERSION lua; do
+for ac_lib in ''  lua$LUA_VERSION \
+                     lua$LUA_SHORT_VERSION \
+                     lua-$LUA_VERSION \
+                     lua-$LUA_SHORT_VERSION \
+                     lua; do
   if test -z "$ac_lib"; then
     ac_res="none required"
   else