fix: convert Makefile from BSD Make to GNU Make syntax

ober

8cccd189b0a983fb000b9d37a86e9f3dd39a9e75

diff --git a/Makefile b/Makefile
index ffb4674..c0e7511 100644
--- a/Makefile
+++ b/Makefile
@@ -4,45 +4,50 @@ LIBDIRS = lib
 CC ?= cc
 CFLAGS = -Wall -Wextra -fPIC -O2
 
-UNAME != uname -s
-SOEXT = .so
-
-.if ${UNAME} == "FreeBSD"
-MOUNT_FLAGS = -DFREEBSD
-.elif ${UNAME} == "Linux"
-MOUNT_FLAGS = -DLINUX
-.elif ${UNAME} == "Darwin"
-MOUNT_FLAGS = -DDARWIN
-SOEXT = .dylib
-.else
-MOUNT_FLAGS =
-.endif
-
-MOUNT_HELPER = src/libchez_fuse_mount${SOEXT}
+UNAME_S := $(shell uname -s)
+ifeq ($(UNAME_S),FreeBSD)
+  MOUNT_FLAGS = -DFREEBSD
+  SHARED_FLAG = -shared
+  SOEXT = .so
+else ifeq ($(UNAME_S),Linux)
+  MOUNT_FLAGS = -DLINUX
+  SHARED_FLAG = -shared
+  SOEXT = .so
+else ifeq ($(UNAME_S),Darwin)
+  MOUNT_FLAGS = -DDARWIN
+  SHARED_FLAG = -dynamiclib
+  SOEXT = .dylib
+else
+  MOUNT_FLAGS =
+  SHARED_FLAG = -shared
+  SOEXT = .so
+endif
+
+MOUNT_HELPER = src/libchez_fuse_mount$(SOEXT)
 
 .PHONY: all clean test vault-test mount umount
 
-all: ${MOUNT_HELPER}
+all: $(MOUNT_HELPER)
 
-${MOUNT_HELPER}: src/mount_helper.c
-	${CC} ${CFLAGS} ${MOUNT_FLAGS} -shared -o ${.TARGET} ${.ALLSRC}
+$(MOUNT_HELPER): src/mount_helper.c
+	$(CC) $(CFLAGS) $(MOUNT_FLAGS) $(SHARED_FLAG) -o $@ $<
 
 clean:
-	rm -f src/libchez_fuse_mount${SOEXT}
+	rm -f src/libchez_fuse_mount.so src/libchez_fuse_mount.dylib
 	find lib -name "*.so" -delete
 	find lib -name "*.wpo" -delete
 
 test: all
-	${SCHEME} --libdirs ${LIBDIRS} --script tests/test-memfs.ss
+	$(SCHEME) --libdirs $(LIBDIRS) --script tests/test-memfs.ss
 
 vault-test: all
-	${SCHEME} --libdirs ${LIBDIRS} --script tests/test-vault.ss
+	$(SCHEME) --libdirs $(LIBDIRS) --script tests/test-vault.ss
 
 mount: all
-	@test -n "${MOUNTPOINT}" || (echo "MOUNTPOINT required: make mount MOUNTPOINT=/tmp/hello" && exit 1)
-	@mkdir -p ${MOUNTPOINT}
-	${SCHEME} --libdirs ${LIBDIRS} --script examples/hello.ss ${MOUNTPOINT}
+	@test -n "$(MOUNTPOINT)" || (echo "MOUNTPOINT required: make mount MOUNTPOINT=/tmp/hello" && exit 1)
+	@mkdir -p $(MOUNTPOINT)
+	$(SCHEME) --libdirs $(LIBDIRS) --script examples/hello.ss $(MOUNTPOINT)
 
 umount:
-	@test -n "${MOUNTPOINT}" || (echo "MOUNTPOINT required" && exit 1)
-	umount ${MOUNTPOINT} 2>/dev/null || true
+	@test -n "$(MOUNTPOINT)" || (echo "MOUNTPOINT required" && exit 1)
+	umount $(MOUNTPOINT) 2>/dev/null || true