dell-flash-unlock: Remove dependency on GNU Make

Use shell scripting in the recipe instead of GNU make's
conditional syntax. This allows the Makefile to work with
the default implementations of make on the BSDs.

Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>

util/dell-flash-unlock/Makefile

@@ -3,16 +3,14 @@
 
 CC=cc
 CFLAGS=-Wall -Wextra -Werror -O2 -pedantic
-ifeq ($(shell uname), OpenBSD)
-	CFLAGS += -l$(shell uname -p)
-endif
-ifeq ($(shell uname), NetBSD)
-	CFLAGS += -l$(shell uname -p)
-endif
 SRCS=dell_flash_unlock.c accessors.c
 
 all: $(SRCS) accessors.h
-	$(CC) $(CFLAGS) $(SRCS) -o dell_flash_unlock
+	CFLAGS="$(CFLAGS)"; \
+	if [ $$(uname) = OpenBSD ] || [ $$(uname) = NetBSD ]; then \
+		CFLAGS="$$CFLAGS -l$$(uname -p)"; \
+	fi; \
+	$(CC) $$CFLAGS $(SRCS) -o dell_flash_unlock
 
 clean:
 	rm -f dell_flash_unlock

util/dell-flash-unlock/README.md

@@ -21,16 +21,13 @@ around 2008 (E6400 era).
   with that option set.
 
 ### OpenBSD/NetBSD/FreeBSD
-- The makefile is not currently compatible with POSIX make; install and use GNU
-  Make (gmake) to build dell-flash-unlock instead of make
 - On OpenBSD/NetBSD/FreeBSD, ensure you are booting with securelevel set to -1.
 
 ### General
 Make sure an AC adapter is plugged into your system
 
-Run `make` (or `gmake` on BSD) to compile the utility, and then run
+Run `make` to compile the utility, and then run `./dell_flash_unlock` with
-`./dell_flash_unlock` with root/superuser permissions and follow the directions
+root/superuser permissions and follow the directions it outputs.
-it outputs.
 
 ## Confirmed supported devices
 - Latitude E6400, E6500