Added BEFORE option

README.md

@@ -84,6 +84,7 @@ GNU gcc + ld is used to create a shared object and get converted into an .efi fi
 | `LIBS`     | additional libraries you want to link with (like "-lm", only static .a libraries allowed)            |
 | `EXTRA`    | any additional object files you might want to link with                                              |
 | `ALSO`     | additional makefile rules to be called                                                               |
+| `BEFORE`   | additional makefile rules to be called before compiling
 | `OUTDIR`   | if given, then your project's object files are generated into this directory (by default not set)    |
 | `USE_GCC`  | set this if you want native GNU gcc + ld + objccopy instead of LLVM Clang + Lld                      |
 | `ARCH`     | the target architecture                                                                              |

uefi/Makefile

@@ -70,7 +70,7 @@ else
 ALLTARGETS = uefi/crt_$(ARCH).o uefi/libuefi.a $(OBJS) $(TARGET)
 endif
 
-all: $(OUTDIR) $(ALLTARGETS) $(EXTRA) $(ALSO)
+all: $(BEFORE) $(OUTDIR) $(ALLTARGETS) $(EXTRA) $(ALSO)
 
 ifneq ($(OUTDIR),)
 $(OUTDIR):