Fix configuring build for OOT build (485)

Makefile

@@ -336,10 +336,10 @@ endif
 all: bin/ bin/dep bin/vendor check_submodules build
 build:
 # Each target is in a different line, so they are executed one after the other even when the processor has multiple cores (when the -j option for the make command is > 1). See: https://www.gnu.org/software/make/manual/html_node/Parallel.html
-	@$(MAKE) -f $(CRAZYFLIE_BASE)/Makefile --no-print-directory clean_version CRAZYFLIE_BASE=$(CRAZYFLIE_BASE)
-	@$(MAKE) -f $(CRAZYFLIE_BASE)/Makefile --no-print-directory compile CRAZYFLIE_BASE=$(CRAZYFLIE_BASE)
-	@$(MAKE) -f $(CRAZYFLIE_BASE)/Makefile --no-print-directory print_version CRAZYFLIE_BASE=$(CRAZYFLIE_BASE)
-	@$(MAKE) -f $(CRAZYFLIE_BASE)/Makefile --no-print-directory size CRAZYFLIE_BASE=$(CRAZYFLIE_BASE)
+	@$(MAKE) --no-print-directory clean_version CRAZYFLIE_BASE=$(CRAZYFLIE_BASE)
+	@$(MAKE) --no-print-directory compile CRAZYFLIE_BASE=$(CRAZYFLIE_BASE)
+	@$(MAKE) --no-print-directory print_version CRAZYFLIE_BASE=$(CRAZYFLIE_BASE)
+	@$(MAKE) --no-print-directory size CRAZYFLIE_BASE=$(CRAZYFLIE_BASE)
 compile: $(PROG).hex $(PROG).bin $(PROG).dfu
 
 bin/:

docs/build_instructions.md

@@ -149,13 +149,6 @@ separate folder with separate configurations.
 Both ```tools/make/config.mk``` and ```current_platform.mk``` are sourced from the current folder
 and not from the Crazyflie firmware folder.
 
-Using this method it is also possible to build a clean Crazyflie firmware directly from command line:
-```
-# Assuming the firmware is clonned in crazyflie-firmware/
-mkdir build && cd build
-make -f ../crazyflie-firmware/Makefile CRAZYFLIE_BASE=../crazyflie-firmware
-```
-
 # Make targets:
 ```
 all        : Shortcut for build