+# List headers for which HAVE_HEADER_H is always true, assuming you are
+# using the appropriate gnulib module. CAUTION: for each "unnecessary"
+# #if HAVE_HEADER_H that you remove, be sure that your project explicitly
+# requires the gnulib module that guarantees the usability of that header.
+gl_assured_headers_ = \
+ cd $(gnulib_dir)/lib && echo *.in.h|sed 's/\.in\.h//g'
+
+# Convert the list of names to upper case, and replace each space with "|".
+az_ = abcdefghijklmnopqrstuvwxyz
+AZ_ = ABCDEFGHIJKLMNOPQRSTUVWXYZ
+gl_header_upper_case_or_ = \
+ $$($(gl_assured_headers_) \
+ | tr $(az_)/.- $(AZ_)___ \
+ | tr -s ' ' '|' \
+ )
+sc_prohibit_always_true_header_tests:
+ @or=$(gl_header_upper_case_or_); \
+ re="HAVE_($$or)_H"; \
+ prohibit='\<'"$$re"'\>' \
+ halt=$$(printf '%s\n' \
+ 'do not test the above HAVE_<header>_H symbol(s);' \
+ ' with the corresponding gnulib module, they are always true') \
+ $(_sc_search_regexp)
+
+# ==================================================================
+gl_other_headers_ ?= \
+ intprops.h \
+ openat.h \
+ stat-macros.h
+
+# Perl -lne code to extract "significant" cpp-defined symbols from a
+# gnulib header file, eliminating a few common false-positives.
+gl_extract_significant_defines_ = \
+ /^\# *define ([^_ (][^ (]*)(\s*\(|\s+\w+)/\
+ && $$2 !~ /(?:rpl_|_used_without_)/\
+ && $$1 !~ /^(?:NSIG|ATTRIBUTE_NORETURN)$$/\
+ and print $$1
+
+# Create a list of regular expressions matching the names
+# of macros that are guaranteed to be defined by parts of gnulib.
+define def_sym_regex
+ gen_h=$(gl_generated_headers_); \
+ (cd $(gnulib_dir)/lib; \
+ for f in *.in.h $(gl_other_headers_); do \
+ perl -lne '$(gl_extract_significant_defines_)' $$f; \
+ done; \
+ ) | sort -u \
+ | grep -Ev '^ATTRIBUTE_NORETURN' \
+ | sed 's/^/^ *# *(define|undef) */;s/$$/\\>/'
+endef
+
+# Don't define macros that we already get from gnulib header files.
+sc_prohibit_always-defined_macros:
+ @if test -d $(gnulib_dir); then \
+ case $$(echo all: | grep -l -f - Makefile) in Makefile);; *) \
+ echo '$(ME): skipping $@: you lack GNU grep' 1>&2; exit 0;; \
+ esac; \
+ $(def_sym_regex) | grep -E -f - $$($(VC_LIST_EXCEPT)) \
+ && { echo '$(ME): define the above via some gnulib .h file' \
+ 1>&2; exit 1; } || :; \
+ fi
+# ==================================================================
+
+# Prohibit checked in backup files.
+sc_prohibit_backup_files:
+ @$(VC_LIST) | grep '~$$' && \
+ { echo '$(ME): found version controlled backup file' 1>&2; \
+ exit 1; } || :
+