[Build] Add Makefile for use with Theos, add .gitignore for build systems, switch Xcode to build with C99 to match Theos

Author: leptos-null

.gitignore

@@ -0,0 +1,14 @@
+# macOS
+.DS_Store
+
+# Theos
+obj/
+.theos/
+
+# Xcode
+xcuserdata/
+xcshareddata/
+build
+
+# VSCode
+.vscode/

Makefile

@@ -0,0 +1,6 @@
+include $(THEOS)/makefiles/common.mk
+
+LIBRARY_NAME = inject_decrypt
+inject_decrypt_FILES = inject_decrypt/inject_decrypt.c
+
+include $(THEOS_MAKE_PATH)/library.mk

inject_decrypt.xcodeproj/project.pbxproj

@@ -163,7 +163,7 @@
 				DEBUG_INFORMATION_FORMAT = dwarf;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
-				GCC_C_LANGUAGE_STANDARD = gnu11;
+				GCC_C_LANGUAGE_STANDARD = c99;
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_OPTIMIZATION_LEVEL = 0;
@@ -222,7 +222,7 @@
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
-				GCC_C_LANGUAGE_STANDARD = gnu11;
+				GCC_C_LANGUAGE_STANDARD = c99;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;