examples: require float_math where needed

Author: maribu

examples/lang_support/official/riot_and_cpp/Makefile

@@ -27,6 +27,8 @@ DEVELHELP ?= 1
 # Change this to 0 show compiler invocation lines by default:
 QUIET ?= 1
 
+USEMODULE += printf_float
+
 # Features required
 FEATURES_REQUIRED += cpp # basic C++ support
 FEATURES_REQUIRED += libstdcpp # libstdc++ support (for #include <cstdio>)

examples/networking/misc/spectrum-scanner/Makefile

@@ -7,6 +7,9 @@ BOARD ?= samr21-xpro
 # This has to be the absolute path to the RIOT base directory:
 RIOTBASE ?= $(CURDIR)/../../../..
 
+# Needed for print_float()
+FEATURES_REQUIRED += float_math
+
 # Define modules that are used
 USEMODULE += gnrc
 USEMODULE += netdev_default