Makefile: Remove `-framework` arguments when building DDHotKey obj files

I was getting warnings that these arguments are unused because we're not
linking anything in this command:

    $ clang -x objective-c \
        -framework Carbon \
        -framework Cocoa \
        -framework Foundation \
        -fobjc-arc \
        -c \
        lib/DDHotKey/DDHotKeyCenter.m
    clang: warning: -framework Carbon: 'linker' input unused [-Wunused-command-line-argument]
    clang: warning: -framework Cocoa: 'linker' input unused [-Wunused-command-line-argument]
    clang: warning: -framework Foundation: 'linker' input unused [-Wunused-command-line-argument]

1 files changed, 0 insertions, 3 deletions

diff --git a/Makefile b/Makefile
index eae7a14..8521325 100644
--- a/Makefile
+++ b/Makefile
@@ -22,9 +22,6 @@ build/include/*.h: lib/DDHotKey/*.h
 lib/DDHotKey/%.o: lib/DDHotKey/%.m
 	clang -x objective-c \
 		-w \
-		-framework Carbon \
-		-framework Cocoa \
-		-framework Foundation \
 		-fobjc-arc \
 		-c \
 		$<