diff --git a/Makefile b/Makefile
index db3f296..894e6e1 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@ IDENTIFIER=net.alkalay.RDM
 
 VERSION=2.2
 
-CC=llvm-g++
+CFLAGS += -std=gnu99
 PACKAGE_BUILD=/usr/bin/pkgbuild
 ARCH_FLAGS=-arch x86_64
 
diff --git a/ResMenuItem.mm b/ResMenuItem.m
similarity index 100%
rename from ResMenuItem.mm
rename to ResMenuItem.m
diff --git a/SRApplicationDelegate.mm b/SRApplicationDelegate.m
similarity index 100%
rename from SRApplicationDelegate.mm
rename to SRApplicationDelegate.m
diff --git a/cmdline.mm b/cmdline.m
similarity index 100%
rename from cmdline.mm
rename to cmdline.m
diff --git a/main.mm b/main.m
similarity index 100%
rename from main.mm
rename to main.m
diff --git a/utils.h b/utils.h
index 8940c38..a55787f 100644
--- a/utils.h
+++ b/utils.h
@@ -21,14 +21,10 @@ typedef union
 	} derived;
 } modes_D4;
 
-extern "C"
-{
- 	void CGSGetCurrentDisplayMode(CGDirectDisplayID display, int* modeNum);
-	void CGSConfigureDisplayMode(CGDisplayConfigRef config, CGDirectDisplayID display, int modeNum);
-	void CGSGetNumberOfDisplayModes(CGDirectDisplayID display, int* nModes);
-	void CGSGetDisplayModeDescriptionOfLength(CGDirectDisplayID display, int idx, modes_D4* mode, int length);
-};
-
+void CGSGetCurrentDisplayMode(CGDirectDisplayID display, int* modeNum);
+void CGSConfigureDisplayMode(CGDisplayConfigRef config, CGDirectDisplayID display, int modeNum);
+void CGSGetNumberOfDisplayModes(CGDirectDisplayID display, int* nModes);
+void CGSGetDisplayModeDescriptionOfLength(CGDirectDisplayID display, int idx, modes_D4* mode, int length);
 
 void CopyAllDisplayModes(CGDirectDisplayID display, modes_D4** modes, int* cnt);
 void SetDisplayModeNum(CGDirectDisplayID display, int modeNum);
diff --git a/utils.mm b/utils.m
similarity index 100%
rename from utils.mm
rename to utils.m