Autotools

User Variables

The GCS defines a set of variables that are sacred to the user. These variables should be referenced by a GNU build system, but never modified by a GNU build system. These so-called user variables include those listed in Table 2-2 for C and C++ programs.

Table 2-2. Some User Variables and Their Purposes

Variable	Purpose
CC	A reference to the system C compiler
CFLAGS	Desired C compiler flags
CXX	A reference to the system C++ compiler
CXXFLAGS	Desired C++ compiler flags
LDFLAGS	Desired linker flags
CPPFLAGS	Desired C/C++ preprocessor flags
. . .

This list is by no means comprehensive, and interestingly, there isn't a comprehensive list to be found in the GCS. In fact, most of these variables come from the documentation for the make utility itself. ...