错误：可能未定义的宏：AS_IF答案

【问题标题】：error: possibly undefined macro: AS_IF错误：可能未定义的宏：AS_IF
【发布时间】：2017-07-19 09:04:07
【问题描述】：

我正在尝试编译 TPM2.0-TSS 项目，但在创建配置脚本时出错：

$ git clone https://github.com/01org/TPM2.0-TSS.git
Cloning into 'TPM2.0-TSS'...
remote: Counting objects: 6522, done.
remote: Total 6522 (delta 0), reused 0 (delta 0), pack-reused 6522
Receiving objects: 100% (6522/6522), 13.99 MiB | 4.44 MiB/s, done.
Resolving deltas: 100% (5081/5081), done.
$
$
$ cd TPM2.0-TSS/
$ ./bootstrap 
Generating file lists: src_vars.mk
libtoolize: putting auxiliary files in '.'.
libtoolize: linking file './ltmain.sh'
libtoolize: putting macros in AC_CONFIG_MACRO_DIRS, 'm4'.
libtoolize: linking file 'm4/libtool.m4'
libtoolize: linking file 'm4/ltoptions.m4'
libtoolize: linking file 'm4/ltsugar.m4'
libtoolize: linking file 'm4/ltversion.m4'
libtoolize: linking file 'm4/lt~obsolete.m4'
configure.ac:14: error: possibly undefined macro: AS_IF
      If this token and others are legitimate, please use m4_pattern_allow.
      See the Autoconf documentation.
configure.ac:28: error: possibly undefined macro: AC_SUBST
configure.ac:31: error: possibly undefined macro: AC_MSG_ERROR
configure:12158: error: possibly undefined macro: AC_MSG_WARN
autoreconf: /usr/bin/autoconf failed with exit status: 1
$

奇怪的是，当我第二次调用bootstap 时，它成功了。

$ ./bootstrap 
Generating file lists: src_vars.mk
configure.ac:4: installing './compile'
configure.ac:5: installing './config.guess'
configure.ac:5: installing './config.sub'
configure.ac:6: installing './install-sh'
configure.ac:6: installing './missing'
Makefile.am: installing './depcomp'
parallel-tests: installing './test-driver'
$

还有一些其他帖子有类似的错误，通过安装pkg-config 解决了它们 - 但我的系统中已经安装了pkg-config。

【问题讨论】：

标签： linux autoconf

【解决方案1】：

终于按照INSTALL.md的提示安装autoconf-archive（info）解决了问题：

$ sudo apt -y update
$ sudo apt -y install \
  autoconf-archive \
  libcmocka0 \
  libcmocka-dev \
  build-essential \
  git \
  pkg-config \
  gcc \
  g++ \
  m4 \
  libtool \
  automake \
  autoconf

进一步检查PKG_CONFIG变量是否设置：

$ env | grep PKG_CONFIG 
PKG_CONFIG=[...]/system/buildroot-x86/output/host/usr/bin/pkg-config
PKG_CONFIG_PATH=[...]/TPM2.0-TSS-INSTALL/lib/pkgconfig/
$
$ unset PKG_CONFIG
$ unset PKG_CONFIG_PATH
$
$ env | grep PKG_CONFIG 
$

【讨论】：