Description:
------------
When trying to configure with --enable-mbstring the error message when the oniguruma package can't be found is below and says the package needed is 'oniguruma'. 

But the package that needs to be installed is typically called 'libonig-dev'. 

Every so often I forget this when compiling on a new system.

It would be better if the probably package name could be displayed in the error message. I had a quick look and couldn't see how it instantly.




Expected result:
----------------
checking for oniguruma... no
configure: error: Package requirements (oniguruma) were not met:

No package 'oniguruma' found - The package required is often called 'libonig-dev'.

Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.

Alternatively, you may set the environment variables ONIG_CFLAGS
and ONIG_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.



Actual result:
--------------
checking for oniguruma... no
configure: error: Package requirements (oniguruma) were not met:

No package 'oniguruma' found

Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.

Alternatively, you may set the environment variables ONIG_CFLAGS
and ONIG_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.