Build display library separately

https://github.com/probonopd/MiniDexed/issues/21#issuecomment-1052477907
Thanks @rsta2

build.sh

@@ -20,12 +20,19 @@ make mrproper || true
 ./configure -r ${RPI} --prefix "${TOOLCHAIN_PREFIX}"
 echo "DEFINE += -DSAVE_VFP_REGS_ON_IRQ" >> libs/circle/Config.mk
 echo "DEFINE += -DREALTIME" >> libs/circle/Config.mk
-make -j$(nproc)
+make -j
+
+# Build additional libraries
+cd libs/circle/addon/display/
+make clean || true
+make -j
+cd ../../../..
+
 cd ..
 
 # Build MiniDexed
 cd src
 make clean || true
-make -j$(nproc)
+make -j
 ls *.img
 cd ..

src/Rules.mk

@@ -17,6 +17,7 @@ LIBS += \
  	$(NEWLIBDIR)/lib/libm.a \
 	$(NEWLIBDIR)/lib/libc.a \
 	$(NEWLIBDIR)/lib/libcirclenewlib.a \
+	$(CIRCLEHOME)/addon/display/libdisplay.a \
 	$(CIRCLEHOME)/addon/SDCard/libsdcard.a \
   	$(CIRCLEHOME)/lib/usb/libusb.a \
  	$(CIRCLEHOME)/lib/input/libinput.a \