The implicit make rule for compiling a C program is %.o:%.c $(CC) $(CPPFLAGS) $(CFLAGS) -c -o $@ $< where the $() syntax expands the variables. As both CPPFLAGS and CFLAGS are used in the compiler call, which you use to define include paths is a matter of personal taste. For instance if foo.c is a … Read more
It depends on the package. If the Makefile is generated by GNU autotools (./configure) you can usually set the target location like so: ./configure –prefix=/somewhere/else/than/usr/local If the Makefile is not generated by autotools, but distributed along with the software, simply open it up in an editor and change it. The install target directory is probably … Read more
Makefile.am is a programmer-defined file and is used by automake to generate the Makefile.in file (the .am stands for automake). The configure script typically seen in source tarballs will use the Makefile.in to generate a Makefile. The configure script itself is generated from a programmer-defined file named either configure.ac or configure.in (deprecated). I prefer .ac … Read more
One significant problem with PKG_CHECK_MODULES is that it causes failures where it should not. If a user installs libfoo in /p/a/t/h and invokes a configure script with LDFLAGS=-L/p/a/t/h, the user is justified in expecting the configury to find libfoo. But, the user also must set PKG_CONFIG_PATH so that the configure script can find foo.pc in … Read more
If you’re using a shell that does simple substitution and the SHELL_VAR variable does not exist (or is blank), then you need to watch out for the edge cases. The following translations will happen: if test $SHELL_VAR = yes; then –> if test = yes; then if test x$SHELL_VAR = xyes; then –> if test … Read more