+ The following variables are used as "make variables" and
+ can be used as an alternative to giving preprocessor,
+ compiler and linker options directly as configuration.
+ The following variables are supported:
+
+ AR The static library archiver.
+ ARFLAGS Flags for the static library archiver.
+ AS The assembler compiler.
+ ASFLAGS Flags for the assembler compiler.
+ CC The C compiler.
+ CFLAGS Flags for the C compiler.
+ CXX The C++ compiler.
+ CXXFLAGS Flags for the C++ compiler.
+ CPP The C/C++ preprocessor.
+ CPPFLAGS Flags for the C/C++ preprocessor.
+ CPPDEFINES List of CPP macro definitions, separated
+ by a platform specific character (':' or
+ space for Unix, ';' for Windows, ',' for
+ VMS). This can be used in place of -D.
+ CPPINCLUDES List of CPP inclusion directories, separated
+ the same way as for CPPDEFINES. This can
+ be used in place of -I.
+ HASHBANGPERL Perl invocation to be inserted after '#!'
+ in public perl scripts.
+ LD The program linker (not used on Unix, $(CC)
+ is used there).
+ LDFLAGS Flags for the shared library, DSO and
+ program linker.
+ LDLIBS Extra libraries to use when linking.
+ Takes the form of a space separated list
+ of library specifications on Unix and
+ Windows, and as a comma separated list of
+ libraries on VMS.
+ RANLIB The library archive indexer.
+ RC The Windows resources manipulator.
+ RCFLAGS Flags for the Windows reources manipulator.
+ RM The command to remove files and directories.
+
+ These can be mixed with flags given on the command line.
+ Any variable assignment resets any corresponding flags
+ given before it, so for example:
+
+ ./config -DFOO CPPFLAGS=-DBAR -DCOOKIE
+
+ Will end up having 'CPPFLAGS=-DBAR -DCOOKIE'.
+
+ Here is how the flags documented above are collected as
+ augmentation of these variables:
+
+ -Dxxx xxx is collected in CPPDEFINES
+ -Ixxx xxx is collected in CPPINCLUDES
+ -Wp,xxx collected in CPPFLAGS
+ -Lxxx collected in LDFLAGS
+ -lxxx collected in LDLIBS
+ -Wp,xxx collected in LDLIBS
+ -rpath xxx collected in LDLIBS
+ -R xxx collected in LDLIBS
+ -framework xxx collected in LDLIBS
+ -static collected in LDLIBS
+ -xxx collected in CFLAGS
+ +xxx collected in CFLAGS
+