Ship its own version of tsearch and friends if not provided by platform.

On GNU based systems the tree related functions (tsearch, tfind, tdestroy)
are provided by the libc (with the interface specification in search.h). On
non-GNU systems this functionality may or may not be available. That's the
case for Android which ships its own, simplified, version of libc called
Bionic. Bionic does not contains neither search.h nor an implementation of
the above mentioned functions.

This patch adds detection for the presence of search.h and if the header file
is not found, it uses an internal version of search.h and functions tsearch,
tfind, and tdestroy. The internal version is based on the source code from
FreeBSD and is compiled if and only if the configure script did not find the
search.h header file.
 -- Jan Janak

1 files changed, 2 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 5f8a71b2..1b21321c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -184,6 +184,8 @@ AC_CHECK_HEADERS([fcntl.h math.h errno.h limits.h stdio.h locale.h sys/stat.h sy
 # Check for optional headers
 AC_CHECK_HEADERS([sys/types.h sys/time.h sys/msg.h netdb.h netinet/in.h netinet/tcp.h time.h sys/socket.h sys/mman.h arpa/inet.h sys/select.h poll.h winsock2.h ws2tcpip.h])
 
+AC_CHECK_HEADERS([search.h], AM_CONDITIONAL(HAVE_TSEARCH, true), AM_CONDITIONAL(HAVE_TSEARCH, false))
+
 # Check for plibc.h from system, if not found, use our own
 AC_CHECK_HEADERS([plibc.h],our_private_plibc_h=0,our_private_plibc_h=1)
 AM_CONDITIONAL(USE_PRIVATE_PLIBC_H, test x$our_private_plibc_h = x1)