There are variations of this question bouncing around SO, but none of them seem to have an answer that solves my problem.
I am running OSX Lion (10.7.3). The latest XCode is installed.
I've installed Postgres using the Postgres.app package from postgresapp.com.
But when I try to install the pg gem, I get a failure:
$ gem install pg -- --with-pg-config=/Applications/Postgres.app/Contents/MacOS/bin/pg_config
Building native extensions. This could take a while...
ERROR: Error installing pg:
ERROR: Failed to build gem native extension.
/Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/bin/ruby extconf.rb --with-pg-config=/Applications/Postgres.app/Contents/MacOS/bin/pg_config
Using config values from /Applications/Postgres.app/Contents/MacOS/bin/pg_config
checking for libpq-fe.h... *** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.
Provided configuration options:
--with-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/bin/ruby
--with-pg
--without-pg
--with-pg-dir
--without-pg-dir
--with-pg-include
--without-pg-include=${pg-dir}/include
--with-pg-lib
--without-pg-lib=${pg-dir}/lib
--with-pg-config
/Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
from /Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:506:in `try_cpp'
from /Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:970:in `block in find_header'
from /Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
from /Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
from /Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from /Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
from /Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from /Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
from /Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
from /Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:969:in `find_header'
from extconf.rb:40:in `<main>'
Gem files will remain installed in /Users/disaacs/.rvm/gems/ruby-1.9.3-p125/gems/pg-0.13.2 for inspection.
Results logged to /Users/disaacs/.rvm/gems/ruby-1.9.3-p125/gems/pg-0.13.2/ext/gem_make.out
The output of the /Applications/Postgres.app/Contents/MacOS/bin/pg_config command is:
$ /Applications/Postgres.app/Contents/MacOS/bin/pg_config
BINDIR = /Applications/Postgres.app/Contents/MacOS/bin
DOCDIR = /Applications/Postgres.app/Contents/MacOS/share/doc
HTMLDIR = /Applications/Postgres.app/Contents/MacOS/share/doc
INCLUDEDIR = /Applications/Postgres.app/Contents/MacOS/include
PKGINCLUDEDIR = /Applications/Postgres.app/Contents/MacOS/include
INCLUDEDIR-SERVER = /Applications/Postgres.app/Contents/MacOS/include/server
LIBDIR = /Applications/Postgres.app/Contents/MacOS/lib
PKGLIBDIR = /Applications/Postgres.app/Contents/MacOS/lib
LOCALEDIR = /Applications/Postgres.app/Contents/MacOS/share/locale
MANDIR = /Applications/Postgres.app/Contents/MacOS/share/man
SHAREDIR = /Applications/Postgres.app/Contents/MacOS/share
SYSCONFDIR = /Applications/Postgres.app/Contents/MacOS/etc
PGXS = /Applications/Postgres.app/Contents/MacOS/lib/pgxs/src/makefiles/pgxs.mk
CONFIGURE = '--prefix=/Users/mattt/Code/heroku/Postgres/Postgres/Vendor/postgres' '--enable-thread-safety' '--with-openssl' '--with-gssapi' '--with-bonjour' '--with-krb5' '--with-libxml' '--with-libxslt' '--with-ossp-uuid' '--with-perl' '--with-python'
CC = gcc
CPPFLAGS = -I/usr/include/libxml2
CFLAGS = -O2 -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wformat-security -fno-strict-aliasing -fwrapv
CFLAGS_SL =
LDFLAGS = -Wl,-dead_strip_dylibs
LDFLAGS_EX =
LDFLAGS_SL =
LIBS = -lpgport -lxslt -lxml2 -lssl -lcrypto -lgssapi_krb5 -lz -lreadline -lm
VERSION = PostgreSQL 9.1.3
All those setting appear to be correct, except for the CONFIGURE variable (which seems to be referring to some other computer --I have no user named mattt).
The contents of the mkmf.log file are
"/usr/bin/gcc-4.2 -o conftest -I/Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1/x86_64-darwin10.8.0 -I/Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1/ruby/backward -I/Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1 -I. -I/Users/disaacs/.rvm/usr/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -I/Applications/Postgres.app/Contents/MacOS/include -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -fno-common -pipe conftest.c -L. -L/Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib -L/Users/disaacs/.rvm/usr/lib -L. -L/usr/local/lib -L/Applications/Postgres.app/Contents/MacOS/lib -lruby.1.9.1 -lpthread -ldl -lobjc "
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: int main() {return 0;}
/* end */
Any suggestions would be appreciated.
I've looked at the extconf.rb file, and after some debugging I've found that it is a call to
find_header ('libpq-fe.h')
that is failing. Not because libpq-fe.h is not there, but because the find_header method itself is failing. I tried running find_header using irb, and got the same error:
$ irb
1.9.3-p125 :001 > require 'mkmf'
=> true
1.9.3-p125 :002 > find_header 'libpq-fe.h'
checking for libpq-fe.h... RuntimeError: The compiler failed to generate an executable file.
You have to install development tools first.
EDIT:
Found out my computer must be even more borked than I thought. I was doing bundle install for another project, and I got a very similar failure installing the sqlite3 gem.
checking for sqlite3.h... *** extconf.rb failed ***
I've never had problems with the sqlite3 gem in the past.
I finally found the cause of the problem! Though I am still uncertain how this problem came about.
Look at the contents of the mkmf.log file that is created when my install command fails (see my original post). It logs an attempt to run the following command
/usr/bin/gcc-4.2 ...and so on...
There is no /usr/bin/gcc-4.2 on my system. There is a gcc, which is symbolically linked to llvm-gcc-4.2. My solution was to create another symbolic link
sudo ln -s llvm-gcc-4.2 gcc-4.2
After making this link, my gem install pg command worked without any problems.
I found the solution to this problem on the Frozen Canuck blog in the post Error Installing Ruby Gem with C Extension. He speculates that the problem can be caused by conflicting versions of XCode. whatever the cause, my eternal thanks!
On OS X Mavericks
sudo ln -s /usr/bin/llvm-gcc /usr/bin/gcc-4.2
works.
I had a similar issue. Following an answer by bobfet1 for a similar issue I was able to get the gem installed by:
sudo env ARCHFLAGS="-arch x86_64" gem install pg -- --with-pg-config=/Applications/Postgres.app/Contents/MacOS/bin/pg_config
Thanks to this guy: http://www.computersnyou.com/2025/
On Mavericks using: xcode-select --install (assuming you have installed Xcode from the app store) works.
Installing xcode from the app store is not enough. You will also need xcode's command line tools. https://developer.apple.com/library/ios/#documentation/DeveloperTools/Conceptual/WhatsNewXcode/Articles/xcode_4_3.html
After installing xcode from the app store, open xcode. Goto Xcode->Open Developer Tool->More Developer Tools Download and install the latest command line tools.
Open a terminal window and run: sudo gem install pg
Similar problem on Mavericks 10.9 -- but it was caused by not having agreed to the Xcode license agreement. Blech.
Run sudo xcodebuild and agree to the junk. The everything works as expected.
I also ran into this issue, for me the answer was updating RVM of all things.
rvm get head
rvm install 1.9.2
I too, am on Mountain Lion, besides the "sudo ln -s /usr/bin/{llvm-,}gcc-4.2" suggested by @grilix, I needed to do:
sudo ln -s /usr/bin/{llvm-,}g++-4.2
After a Mavericks upgrade...
Reinstall your ruby version.
rvm uninstall 1.9.2-p320
then
rvm install 1.9.2-p320
or whatever version of ruby you have.
I am on Mountain Lion, and the accepted answer from Dave Isaacs worked for me. I also had to do
sudo ln -s llvm-g++-4.2 g++-4.2
Rather than updating RVM itself (https://stackoverflow.com/a/10430742/2807795), as above, it was the reinstallation of Ruby 2.0.0-p247 that did the trick, after trying all the other steps above without success.
rvm get head
rvm install 2.0.0
$ gem install pg
If that failed:
$ sudo gem install pg
Then, if that failed:
$ sudo find / -name “pg_config”
After you find pg_config's location, run this to finally install it:
$ sudo gem install pg --with-pg-config=/usr/local/Cellar/postgresql/9.5.1/bin/pg_config
Of course, you'll want to change the path to wherever you found pg_config.
Then, check your installed gems with gem list, and it should show something like this:
More information can be found in my guide.
If the output includes:
/Users/disaacs/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': \
The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
then there really is something amiss with your compilation environment. Especially when the failure is the very first test that extconf.rb runs.
If you have XCode installed, then perhaps you don't have the command-line tools component of XCode installed? They were recently split out from XCode proper, so you need to install them separately.
来源：https://stackoverflow.com/questions/10344821/gem-install-pg-doesnt-work-on-osx-lion