ifnamesto List Conditionals
ifnames can help you write configure.ac for a software
package. It prints the identifiers that the package already uses in C
preprocessor conditionals. If a package has already been set up to have
ifnames can thus help you figure out what its
configure needs to check for. It may help fill in some gaps in a
configure.ac generated by
autoscan (see autoscan Invocation).
ifnames scans all of the C source files named on the command line
(or the standard input, if none are given) and writes to the standard
output a sorted list of all the identifiers that appear in those files
directives. It prints each identifier on a line, followed by a
space-separated list of the files in which that identifier occurs.
ifnames accepts the following options:
Print a summary of the command line options and exit.
Print the version number of Autoconf and exit.