automake: Standard Configuration Variables

1 
1 2.2.4 Standard Configuration Variables
1 --------------------------------------
1 
1 The GNU Coding Standards also define a set of standard configuration
1 variables used during the build.  Here are some:
1 
1 ‘CC’
1      C compiler command
1 ‘CFLAGS’
1      C compiler flags
1 ‘CXX’
1      C++ compiler command
1 ‘CXXFLAGS’
1      C++ compiler flags
1 ‘LDFLAGS’
1      linker flags
1 ‘CPPFLAGS’
1      C/C++ preprocessor flags
1 ...
1 
1    ‘configure’ usually does a good job at setting appropriate values for
1 these variables, but there are cases where you may want to override
1 them.  For instance you may have several versions of a compiler
1 installed and would like to use another one, you may have header files
1 installed outside the default search path of the compiler, or even
1 libraries out of the way of the linker.
1 
1    Here is how one would call ‘configure’ to force it to use ‘gcc-3’ as
1 C compiler, use header files from ‘~/usr/include’ when compiling, and
1 libraries from ‘~/usr/lib’ when linking.
1 
1      ~/amhello-1.0 % ./configure --prefix ~/usr CC=gcc-3 \
1      CPPFLAGS=-I$HOME/usr/include LDFLAGS=-L$HOME/usr/lib
1 
1    Again, a full list of these variables appears in the output of
1 ‘./configure --help’.
1