Remove g++ support from the [C]Make files.

Move all '.cpp' files to '.c'.
Rename comments from 'cpp' to 'c'.

JerryScript-DCO-1.0-Signed-off-by: Roland Takacs rtakacs.u-szeged@partner.samsung.com
JerryScript-DCO-1.0-Signed-off-by: Robert Sipka rsipka.uszeged@partner.samsung.com

targets/esp8266/Makefile.esp8266

@@ -44,8 +44,8 @@ ESP_LIBS_INC :=$(ESP_LIBS_INC);$(ESP_INC2)/lwip
 ESP_LIBS_INC :=$(ESP_LIBS_INC);$(ESP_INC2)/ssl
 
 # jerry related source files
-JERRY_BUILD_FILES := $(SRCPATH)/jerry_extapi.cpp
-JERRY_BUILD_FILES := $(JERRY_BUILD_FILES);$(SRCPATH)/jerry_run.cpp
+JERRY_BUILD_FILES := $(SRCPATH)/jerry_extapi.c
+JERRY_BUILD_FILES := $(JERRY_BUILD_FILES);$(SRCPATH)/jerry_run.c
 
 
 .PHONY: jerry js2c mbed check-env flash clean
@@ -64,7 +64,6 @@ jerry:
 	 -DCMAKE_TOOLCHAIN_FILE=build/configs/toolchain_external.cmake \
 	 -DEXTERNAL_CMAKE_SYSTEM_PROCESSOR=xtensia-lx106 \
 	 -DEXTERNAL_CMAKE_C_COMPILER=xtensa-lx106-elf-gcc \
-	 -DEXTERNAL_CMAKE_CXX_COMPILER=xtensa-lx106-elf-g++ \
 	 -DEXTERNAL_BUILD_ENTRY_FILE="$(JERRY_BUILD_FILES)" \
 	 -DEXTERNAL_COMPILE_FLAGS="$(ESP_CFLAGS)" \
 	 -DEXTERNAL_LIBC_INTERFACE="$(ESP_INC)" \

targets/mbedk64f/Makefile.mbedk64f

@@ -44,7 +44,6 @@ jerry:
 	 -DUSE_COMPILER_DEFAULT_LIBC=YES \
 	 -DEXTERNAL_CMAKE_SYSTEM_PROCESSOR=arm7-m \
 	 -DEXTERNAL_CMAKE_C_COMPILER=arm-none-eabi-gcc \
-	 -DEXTERNAL_CMAKE_CXX_COMPILER=arm-none-eabi-g++ \
 	 -DEXTERNAL_COMPILE_FLAGS="$(EXT_CFLAGS)" \
 	 -DEXTERNAL_MEM_HEAP_SIZE_KB=$(JERRYHEAP)
 

targets/mbedk64f/readme.md

@@ -73,8 +73,8 @@ JerryScript led flashing sample program in js folder.
 
 All `.js` files in `js` folder are executed, with `main.js` in first order.
 `sysloop()` function in main.js is called periodically in every 100msec by
-below code in `main.cpp` `jerry_loop()`, which calls `js_loop()` in
-`jerry_mbedk64f.cpp`
+below code in `main.c` `jerry_loop()`, which calls `js_loop()` in
+`jerry_mbedk64f.c`
 
 ```
   minar::Scheduler::postCallback(jerry_loop)

targets/nuttx-stm32f4/Makefile.nuttx

@@ -42,8 +42,7 @@ all:
 	 -DCMAKE_TOOLCHAIN_FILE=build/configs/toolchain_external.cmake \
 	 -DEXTERNAL_CMAKE_SYSTEM_PROCESSOR=armv7l-hf \
 	 -DEXTERNAL_CMAKE_C_COMPILER=arm-none-eabi-gcc \
-	 -DEXTERNAL_CMAKE_CXX_COMPILER=arm-none-eabi-g++ \
-	 -DEXTERNAL_BUILD_ENTRY_FILE=./targets/nuttx-stm32f4/main-nuttx.cpp \
+	 -DEXTERNAL_BUILD_ENTRY_FILE=./targets/nuttx-stm32f4/main-nuttx.c \
 	 -DEXTERNAL_COMPILE_FLAGS="$(EXT_CFLAGS)" \
 	 -DEXTERNAL_LIBC_INTERFACE=$(NUTTXINC) \
 	 -DEXTERNAL_CMAKE_SYSTEM_PROCESSOR=arm \