doc: Add gcc to list of ESP-IDF prerequisite packages

Closes https://github.com/espressif/esp-idf/issues/1842#issuecomment-380274150

docs/en/get-started/linux-setup.rst

@@ -10,11 +10,11 @@ To compile with ESP-IDF you need to get the following packages:
 
 - CentOS 7::
 
-    sudo yum install git wget make ncurses-devel flex bison gperf python pyserial
+    sudo yum install gcc git wget make ncurses-devel flex bison gperf python pyserial
 
 - Ubuntu and Debian::
 
-    sudo apt-get install git wget make libncurses-dev flex bison gperf python python-serial
+    sudo apt-get install gcc git wget make libncurses-dev flex bison gperf python python-serial
 
 - Arch::
 

docs/zh_CN/get-started/linux-setup.rst

@@ -9,11 +9,11 @@ Linux 平台工具链的标准设置
 
 - CentOS 7::
 
-    sudo yum install git wget make ncurses-devel flex bison gperf python pyserial
+    sudo yum install gcc git wget make ncurses-devel flex bison gperf python pyserial
 
 - Ubuntu and Debian::
 
-    sudo apt-get install git wget make libncurses-dev flex bison gperf python python-serial
+    sudo apt-get install gcc git wget make libncurses-dev flex bison gperf python python-serial
 
 - Arch::