2.4 Using Automake

You can simply use PKG_CHECK_MODULES macro with pkg-config:

PKG_CHECK_MODULES([GPGME], [gpgme >= 1.23.1])

Alternatively, instead of using pkg-config, for building on an environment with no pkg-config, GPGME provides an extension to Automake that does all the work for you. Please note that it is required to have gpgrt-config from libgpg-error installed in this case.

Macro: AM_PATH_GPGME ([minimum-version], [action-if-found], [action-if-not-found]) ¶

Check whether GPGME (at least version minimum-version, if given) exists on the host system. If it is found, execute action-if-found, otherwise do action-if-not-found, if given.

This macro locates for gpgme.pc, with cross-compile support.

Additionally, the function defines GPGME_CFLAGS to the flags needed for compilation of the program to find the gpgme.h header file, and GPGME_LIBS to the linker flags needed to link the program to the GPGME library.

AM_PATH_GPGME_PTHREAD was provided to check for the version of GPGME with the native pthread implementation, and it defined GPGME_PTHREAD_CFLAGS and GPGME_PTHREAD_LIBS. Since version 1.8.0 this is no longer necessary, as GPGME itself is thread safe. Please use plain AM_PATH_GPGME instead, with GPGME_CFLAGS and GPGME_LDFLAGS.

You can use the defined Autoconf variables like this in your Makefile.am:

AM_CPPFLAGS = $(GPGME_CFLAGS)
LDADD = $(GPGME_LIBS)