make: adjust number of jobs to available threads

Previously some builds used a hardcoded number of 8 and others
didn't set it at all falling back to a single threaded build.

This still isn't ideal though. What we actually want is to fix up
or Makefile to allow builders to pass the number of jobs to the toplevel
and then a buildserver can distribute the available jobs across the
targets allowing inter-target parallelism.
For now, this already is a clear improvement.

The fribidi build appears to have a borked dependency on generated
sources when running from a subdir, which resulted in parallel builds
sometimes failing. To fix this the relevant header is now generated
explicitly before other build steps.

Author: TheOneric

Makefile

@@ -28,8 +28,9 @@ build/lib/fribidi/configure: lib/fribidi $(wildcard $(BASE_DIR)build/patches/fri
 $(DIST_DIR)/lib/libfribidi.a: build/lib/fribidi/configure
 	cd build/lib/fribidi && \
 	$(call CONFIGURE_AUTO) && \
-	emmake make -C lib/ install && \
-	emmake make install-pkgconfigDATA
+	$(JSO_MAKE) -C lib/ fribidi-unicode-version.h && \
+	$(JSO_MAKE) -C lib/ install && \
+	$(JSO_MAKE) install-pkgconfigDATA
 
 build/lib/expat/configured: lib/expat
 	$(call PREPARE_SRC_VPATH,expat)
@@ -45,8 +46,8 @@ $(DIST_DIR)/lib/libexpat.a: build/lib/expat/configured
 		-DEXPAT_BUILD_TESTS=off \
 		-DEXPAT_BUILD_TOOLS=off \
 	&& \
-	emmake make -j8 && \
-	emmake make install
+	$(JSO_MAKE) && \
+	$(JSO_MAKE) install
 
 build/lib/brotli/js/decode.js: build/lib/brotli/configured
 build/lib/brotli/js/polyfill.js: build/lib/brotli/configured
@@ -58,8 +59,8 @@ $(DIST_DIR)/lib/libbrotlidec.a: $(DIST_DIR)/lib/libbrotlicommon.a
 $(DIST_DIR)/lib/libbrotlicommon.a: build/lib/brotli/configured
 	cd build/lib/brotli && \
     $(call CONFIGURE_CMAKE) && \
-    emmake make -j8 && \
-	emmake make install
+    $(JSO_MAKE) && \
+	$(JSO_MAKE) install
 	# Normalise static lib names
 	cd $(DIST_DIR)/lib/ && \
 	for lib in *-static.a ; do mv "$$lib" "$${lib%-static.a}.a" ; done
@@ -79,8 +80,8 @@ build/lib/freetype/build_hb/dist_hb/lib/libfreetype.a: $(DIST_DIR)/lib/libbrotli
 			--with-brotli=yes \
 			--without-harfbuzz \
 		&& \
-		emmake make -j8 && \
-		emmake make install
+		$(JSO_MAKE) && \
+		$(JSO_MAKE) install
 
 # Harfbuzz
 build/lib/harfbuzz/configure: lib/harfbuzz $(wildcard $(BASE_DIR)build/patches/harfbuzz/*.patch)
@@ -96,7 +97,7 @@ $(DIST_DIR)/lib/libharfbuzz.a: build/lib/freetype/build_hb/dist_hb/lib/libfreety
 		--with-freetype \
 	&& \
 	cd src && \
-	emmake make -j8 install-libLTLIBRARIES install-pkgincludeHEADERS install-pkgconfigDATA
+	$(JSO_MAKE) install-libLTLIBRARIES install-pkgincludeHEADERS install-pkgconfigDATA
 
 # Freetype with Harfbuzz
 $(DIST_DIR)/lib/libfreetype.a: $(DIST_DIR)/lib/libharfbuzz.a $(DIST_DIR)/lib/libbrotlidec.a
@@ -106,8 +107,8 @@ $(DIST_DIR)/lib/libfreetype.a: $(DIST_DIR)/lib/libharfbuzz.a $(DIST_DIR)/lib/lib
 		--with-brotli=yes \
 		--with-harfbuzz \
 	&& \
-	emmake make -j8 && \
-	emmake make install
+	$(JSO_MAKE) && \
+	$(JSO_MAKE) install
 
 # Fontconfig
 build/lib/fontconfig/configure: lib/fontconfig $(wildcard $(BASE_DIR)build/patches/fontconfig/*.patch)
@@ -120,9 +121,9 @@ $(DIST_DIR)/lib/libfontconfig.a: $(DIST_DIR)/lib/libharfbuzz.a $(DIST_DIR)/lib/l
 		--disable-docs \
 		--with-default-fonts=/fonts \
 	&& \
-	emmake make -C src/ install && \
-	emmake make -C fontconfig/ install && \
-	emmake make install-pkgconfigDATA
+	$(JSO_MAKE) -C src/ install && \
+	$(JSO_MAKE) -C fontconfig/ install && \
+	$(JSO_MAKE) install-pkgconfigDATA
 
 # libass --
 
@@ -137,8 +138,8 @@ $(DIST_DIR)/lib/libass.a: $(DIST_DIR)/lib/libfontconfig.a $(DIST_DIR)/lib/libhar
 		--disable-asm \
 		--enable-fontconfig \
 	&& \
-	emmake make -j8 && \
-	emmake make install
+	$(JSO_MAKE) && \
+	$(JSO_MAKE) install
 
 # SubtitleOctopus.js
 OCTP_DEPS = \

functions.mk

@@ -43,6 +43,8 @@ define CONFIGURE_CMAKE
 	emcmake cmake -S "$(or $(1),.)" -DCMAKE_INSTALL_PREFIX="$(DIST_DIR)"
 endef
 
+# FIXME: Propagate jobserver info with $(MAKE) and set up our makefile for fully parallel builds
+JSO_MAKE := emmake make -j "$(shell nproc)"
 
 ## Clean and git related