Fix the CI; Disregard last commit

The race condition didn't trigger when I tested it, so I assumed I had
solved it...

.gitlab-ci.yml

@@ -45,6 +45,8 @@ build:redox:
         - export XARGO_RUST_SRC="$PWD/rust/src"
 
         # Main script
+        - make -j `nproc` headers
+        - make -j `nproc` install-headers DESTDIR="$PWD/prefix/$TARGET"
         - make -j `nproc` all
 
 test:linux:

Makefile

@@ -27,12 +27,11 @@ SRC=\
 	src/* \
 	src/*/* \
 	src/*/*/* \
-	src/*/*/*/* \
-	headers # Used by compiler-builtins
+	src/*/*/*/*
 
 .PHONY: all clean fmt headers install install-headers libs test
 
-all: headers libs
+all: | headers libs
 
 clean:
 	$(CARGO) clean
@@ -180,7 +179,7 @@ $(BUILD)/include: $(SRC)
 	mv [email protected] $@
 	touch $@
 
-$(BUILD)/openlibm: openlibm headers
+$(BUILD)/openlibm: openlibm
 	rm -rf $@ [email protected]
 	mkdir -p $(BUILD)
 	cp -r $< [email protected]
@@ -190,7 +189,7 @@ $(BUILD)/openlibm: openlibm headers
 $(BUILD)/openlibm/libopenlibm.a: $(BUILD)/openlibm $(BUILD)/include
 	$(MAKE) CC=$(CC) CPPFLAGS="-fno-stack-protector -I$(shell pwd)/include -I $(shell pwd)/$(BUILD)/include" -C $< libopenlibm.a
 
-$(BUILD)/pthreads-emb: pthreads-emb headers
+$(BUILD)/pthreads-emb: pthreads-emb
 	rm -rf $@ [email protected]
 	mkdir -p $(BUILD)
 	cp -r $< [email protected]