Added 'elf' extension to C ignore as one of the output binary formats, synced C++ and C binary output

C++.gitignore

@@ -30,3 +30,7 @@
 *.exe
 *.out
 *.app
+*.i*86
+*.x86_64
+*.hex
+*.elf

C.gitignore

@@ -35,6 +35,7 @@
 *.i*86
 *.x86_64
 *.hex
+*.elf
 
 # Debug files
 *.dSYM/