From 31e9396bf215cbaf224b99617ef683950f0aae02 Mon Sep 17 00:00:00 2001
From: Guillem Jover <guillem@hadrons.org>
Date: Wed, 13 Mar 2024 00:56:07 +0100
Subject: [PATCH] build: Only install time struct conversion macros where
 missing

These macros are available in several systems, and we should not install
the man pages for them, otherwise we might end up shadowing the system
man pages if present.
---
 configure.ac          | 15 +++++++++++++++
 m4/libbsd-compiler.m4 | 16 ++++++++++++++++
 man/Makefile.am       |  9 +++++++--
 3 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index c7c2e13..09bc0f4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -42,6 +42,8 @@ LIBBSD_LINKER_VERSION_SCRIPT
 
 is_windows=no
 
+api_time_macros=unknown
+
 abi_accmode=unknown
 abi_arc4random=unknown
 abi_arc4random_stir=unknown
@@ -86,6 +88,8 @@ abi_wcsl=unknown
 
 AS_CASE([$host_os],
   [*-gnu* | gnu*], [
+    api_time_macros=no
+
     abi_accmode=yes
     # DROP: On glibc >= 2.36.
     #abi_arc4random=no
@@ -145,6 +149,8 @@ AS_CASE([$host_os],
     abi_wcsl=yes
   ],
   [*-musl*], [
+    api_time_macros=no
+
     abi_accmode=yes
     abi_arc4random=yes
     abi_arc4random_stir=yes
@@ -209,6 +215,8 @@ AS_CASE([$host_os],
     abi_wcsl=yes
   ],
   [darwin*], [
+    api_time_macros=no
+
     abi_accmode=no
     abi_arc4random=no
     abi_arc4random_stir=no
@@ -255,6 +263,8 @@ AS_CASE([$host_os],
     abi_wcsl=no
   ],
   [solaris2*], [
+    api_time_macros=yes
+
     abi_accmode=yes
     abi_arc4random=no
     abi_arc4random_stir=no
@@ -301,6 +311,8 @@ AS_CASE([$host_os],
     abi_wcsl=yes
   ],
   [aix*], [
+    api_time_macros=yes
+
     abi_accmode=yes
     abi_arc4random=yes
     abi_arc4random_stir=yes
@@ -545,6 +557,9 @@ AC_CHECK_FUNCS([\
 
 AM_CONDITIONAL([HAVE_GETENTROPY], [test "x$ac_cv_func_getentropy" = "xyes"])
 
+# API selection
+LIBBSD_SELECT_API([time_macros], [time struct conversion macros])
+
 # ABI selection
 LIBBSD_SELECT_ABI([accmode], [setmode()/getmode()])
 LIBBSD_SELECT_ABI([arc4random], [arc4random() API])
diff --git a/m4/libbsd-compiler.m4 b/m4/libbsd-compiler.m4
index 0708f57..ace5ce1 100644
--- a/m4/libbsd-compiler.m4
+++ b/m4/libbsd-compiler.m4
@@ -71,6 +71,22 @@ int main() { return rc; }
     [test "$libbsd_cv_gnu_init_array_support" = yes])
 ])
 
+# LIBBSD_SELECT_API(name, desc)
+# -----------------
+AC_DEFUN([LIBBSD_SELECT_API], [
+  AS_IF([test -z "$AS_TR_SH([api_$1])"], [
+    AC_MSG_ERROR([missing API selection for $1])
+  ], [test "$AS_TR_SH([api_$1])" = "unknown"], [
+    AC_MSG_ERROR([unknown ABI selection for $1])
+  ], [test "$AS_TR_SH([api_$1])" = "yes"], [
+    AC_DEFINE(AS_TR_CPP([LIBBSD_API_$1]), [1], [Provide API for $2])
+  ], [
+    AC_DEFINE(AS_TR_CPP([LIBBSD_API_$1]), [0])
+  ])
+  AM_CONDITIONAL(AS_TR_CPP([API_$1]),
+    [test "x$AS_TR_SH([api_$1])" = "xyes"])
+])
+
 # LIBBSD_SELECT_ABI(name, desc)
 # -----------------
 AC_DEFUN([LIBBSD_SELECT_ABI], [
diff --git a/man/Makefile.am b/man/Makefile.am
index cb2252b..02c8ffb 100644
--- a/man/Makefile.am
+++ b/man/Makefile.am
@@ -141,8 +141,6 @@ dist_man_MANS = \
 	TAILQ_PREV.3bsd \
 	TAILQ_REMOVE.3bsd \
 	TAILQ_SWAP.3bsd \
-	TIMESPEC_TO_TIMEVAL.3bsd \
-	TIMEVAL_TO_TIMESPEC.3bsd \
 	be16dec.3bsd \
 	be16enc.3bsd \
 	be32dec.3bsd \
@@ -182,6 +180,13 @@ dist_man_MANS = \
 	tree.3bsd \
 	# EOL
 
+if API_TIME_MACROS
+dist_man_MANS += \
+	TIMESPEC_TO_TIMEVAL.3bsd \
+	TIMEVAL_TO_TIMESPEC.3bsd \
+	# EOL
+endif
+
 if ABI_ACCMODE
 dist_man_MANS += \
 	getmode.3bsd \