make.sh: Introduce MAX_PARALLELISM

This will now adjust MAKETUNING to not launch more processes
than MAX_PARALLELISM. Handy to limit builds that use a lot of memory.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

lfs/Config

@@ -33,7 +33,15 @@
 # Cleanup environment from any variables
 unexport BUILD_ARCH BUILD_PLATFORM BUILDTARGET CROSSTARGET TOOLCHAIN TOOLS_DIR
 
-MAKETUNING = -j $(DEFAULT_PARALLELISM)
+PARALLELISM = $(shell echo $$( \
+	if [ -n "$(MAX_PARALLELISM)" ] && [ $(MAX_PARALLELISM) -lt $(DEFAULT_PARALLELISM) ]; then \
+		echo $(MAX_PARALLELISM); \
+	else \
+		echo $(DEFAULT_PARALLELISM); \
+	fi) \
+)
+
+MAKETUNING = -j $(PARALLELISM)
 
 ifeq "$(BUILD_ARCH)" "aarch64"
 	IS_64BIT = 1

lfs/boost

@@ -38,7 +38,7 @@ CXXFLAGS  += -O3 -fno-strict-aliasing
 # The compiler uses a lot of memory to compile boost, hence we reduce
 # the total number of processes a little bit to be able to build on
 # smaller machines
-override MAKETUNING = -j$(shell echo $$(( $(SYSTEM_MEMORY) / 512)))
+MAX_PARALLELISM = $(shell echo $$(( $(SYSTEM_MEMORY) / 512)))
 
 CONFIGURE_OPTIONS = \
 	--prefix=/usr \