已安装gcc编译器，但./configure还是提示找不到编译器（分析）

1、编译nginx前， ./configure检查提示找不到C编译器

[root@test nginx-1.12.]# ./configure
checking for OS
 + Linux 3.10.-.el7.x86_64 x86_64
checking for C compiler ... not found

2、重装gcc编译器后，还是提示找不到C编译器

[root@test nginx-1.12.]# yum -y reinstall gcc gcc-c++ autoconf automake make
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.aliyun.com
 * epel: mirrors.tuna.tsinghua.edu.cn
 * extras: mirrors.aliyun.com
 * updates: mirrors..com
Resolving Dependencies
--> Running transaction check
---> Package autoconf.noarch :2.69-.el7 will be reinstalled
---> Package automake.noarch :1.13.-.el7 will be reinstalled
---> Package gcc.x86_64 :4.8.-.el7_6. will be reinstalled
---> Package gcc-c++.x86_64 :4.8.-.el7_6. will be reinstalled
---> Package make.x86_64 :3.82-.el7 will be reinstalled
--> Finished Dependency Resolution
Installed:
  autoconf.noarch :2.69-.el7       automake.noarch :1.13.-.el7   gcc.x86_64 :4.8.-.el7_6.
  gcc-c++.x86_64 :4.8.-.el7_6.   make.x86_64 :3.82-.el7       

Complete!
[root@test nginx-1.12.]# ./configure
checking for OS
 + Linux 3.10.-.el7.x86_64 x86_64
checking for C compiler ... not found

3、网上找一个hello world C程序代码，尝试编译，提示 cannot find 'ld'

[root@test ~]# vim hello_world.c
---------------------------------------
#include <stdio.h>
void main()
{
        printf("Hello World \n");
}
---------------------------------------
[root@test ~]# gcc hello_world.c
collect2: fatal error: cannot find 'ld'
compilation terminated.

4、到另一台可正常编译电脑，查找ld位置

[root@xdc tmp]# which ld
/usr/bin/ld

5、回到问题机器，发现/usr/bin/ld有这个文件，但是which ld，找不到该文件

[root@test]# ll /usr/bin/ld
lrwxrwxrwx.  root root  May   : /usr/bin/ld -> /etc/alternatives/ld
[root@test nginx-1.12.]# which ld
/usr/bin/which: no ld in (/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin)

6、ll /usr/bin/ld 发现该文件最终链接到/usr/bin/ld.bfd，但是，最终的源文件没有可执行权限

[root@test nginx-1.12.]# ll /usr/bin/ld
lrwxrwxrwx.  root root  May   : /usr/bin/ld -> /etc/alternatives/ld
[root@test nginx-1.12.]# ll /etc/alternatives/ld
lrwxrwxrwx.  root root  May   : /etc/alternatives/ld -> /usr/bin/ld.bfd
[root@test nginx-1.12.]# ll /usr/bin/ld.bfd
-rw-rw-rw-.  root root  Oct    /usr/bin/ld.bfd

7、给/usr/bin/ld.bfd文件添加执行权限，编译helloworld成功，./configure 通过gcc环境检查

[root@test ~]# chmod +x /usr/bin/ld.bfd   //添加执行权限
[root@test ~]# which ld
/usr/bin/ld
[root@test ~]# gcc hello_world.c  //编译成功
[root@test ~]# ./
a.out         create.sh       nginx-1.12./ .pki/         .ssh/
[root@test ~]# ./a.out
Hello World
[root@test ~]# cd nginx-1.12./
[root@test nginx-1.12.]# ./configure
checking for OS
 + Linux 3.10.-.el7.x86_64 x86_64
checking for C compiler ... found
 + using GNU C compiler
 + gcc version: 4.8.  (Red Hat 4.8.-) (GCC)
checking for gcc -pipe switch ... found
checking for -Wl,-E switch ... found
checking for gcc builtin atomic operations ... found

8、如果gcc编译时，提示找不到下面其中一个或多个文件，也可通过 yum -y reinstall binutils 重新安装工具集

GNU Binutils

---

The GNU Binutils are a collection of binary tools. The main ones are:

• ld - the GNU linker.
• as - the GNU assembler.

But they also include:

• addr2line - Converts addresses into filenames and line numbers.
• ar - A utility for creating, modifying and extracting from archives.
• c++filt - Filter to demangle encoded C++ symbols.
• dlltool - Creates files for building and using DLLs.
• gold - A new, faster, ELF only linker, still in beta test.
• gprof - Displays profiling information.
• nlmconv - Converts object code into an NLM.
• nm - Lists symbols from object files.
• objcopy - Copies and translates object files.
• objdump - Displays information from object files.
• ranlib - Generates an index to the contents of an archive.
• readelf - Displays information from any ELF format object file.
• size - Lists the section sizes of an object or archive file.
• strings - Lists printable strings from files.
• strip - Discards symbols.
• windmc - A Windows compatible message compiler.
• windres - A compiler for Windows resource files.