Fix bug in error handling where __sub would be clobbered.
diff --git a/share/jmk/dir-locals.el b/share/jmk/dir-locals.el
index 0f6ea64..c8688db 100644
--- a/share/jmk/dir-locals.el
+++ b/share/jmk/dir-locals.el
@@ -1,6 +1,6 @@
 ((nil . ((eval
 		  . (let ((path (expand-file-name (or buffer-file-name "."))))
 			  (setq-local flycheck-clang-include-path
-						(jmk-includes-for path)
-						flycheck-clang-args
-						(jmk-other-flags-for path)))))))
+						  (jmk-includes-for path)
+						  flycheck-clang-args
+						  (jmk-other-flags-for path)))))))
diff --git a/share/jmk/jmk-flycheck.el b/share/jmk/jmk-flycheck.el
index a1ab539..661f7e3 100644
--- a/share/jmk/jmk-flycheck.el
+++ b/share/jmk/jmk-flycheck.el
@@ -43,3 +43,5 @@
 		 (stripped (mapcar #'string-trim not-includes)))
 	stripped))
 
+(provide 'jmk-flycheck)
+;;; jmk-flycheck.el ends here
diff --git a/share/jmk/jmk.m4 b/share/jmk/jmk.m4
index be6fe3d..aa3ad79 100644
--- a/share/jmk/jmk.m4
+++ b/share/jmk/jmk.m4
@@ -45,7 +45,7 @@
         $1, `debug', `CFLAGS += -g
 ASMFLAGS += -Fdwarf',
         $1, `32', `CFLAGS += -m32',
-        $1, `warn', `CFLAGS += -Wall -Wno-unused-function -Wno-unused-variable -Wno-incompatible-pointer-types',
+        $1, `warn', `CFLAGS += -Wall -Wextra -Wno-unused-function -Wno-unused-variable -Wno-incompatible-pointer-types',
         $1, `nasm', `ASM = nasm',
 		$1, `glossaries', `LATEX_MAKE_GLOSSARIES = 1',
 		$1, xelatex, `LATEXC = xelatex')')