package/environment-setup: add cmake alias

In order to simplify the usage of a buildroot toolchain within
the buildroot shell, a "cmake" alias is provided to call cmake
with the correct toolchain file and options.

Signed-off-by: Angelo Compagnucci <angelo@amarulasolutions.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/environment-setup/environment-setup

@@ -12,6 +12,7 @@ Some tips:
 * Standard autotools variables (CC, LD, CFLAGS) are exported
 * To configure do "./configure $CONFIGURE_FLAGS" or use
   the "configure" alias
+* To build CMake-based projects, use the "cmake" alias
 
 EOF
 SDK_PATH=$(dirname $(realpath "${BASH_SOURCE[0]}"))

package/environment-setup/environment-setup.mk

@@ -22,6 +22,9 @@ define HOST_ENVIRONMENT_SETUP_INSTALL_CMDS
 		--program-prefix=\"\n" >> $(ENVIRONMENT_SETUP_FILE)
 	printf "alias configure=\"./configure \$${CONFIGURE_FLAGS}\"\n" \
 		>> $(ENVIRONMENT_SETUP_FILE)
+	printf "alias cmake=\"cmake \
+		-DCMAKE_TOOLCHAIN_FILE=$(HOST_DIR)/share/buildroot/toolchainfile.cmake \
+		-DCMAKE_INSTALL_PREFIX=/usr\"\n" >> $(ENVIRONMENT_SETUP_FILE)
 	$(SED) 's%$(HOST_DIR)%\$$SDK_PATH%g' \
 		-e 's%$(HOST_DIR)/bin/%%g' \
 		-e '/^export "PATH=/c\' \