On UN*X, make sure we can find inflate() in libz.

For example, on at least some versions of Fedora, if you have a 64-bit
machine, have both the 32-bit and 64-bit versions of the run-time zlib
package installed, and have only the *32-bit* version of the zlib
development package installed, it'll find the header, and think it can
use zlib, and will use it in subsequent tests, but it'll try and link
64-bit test programs with the 32-bit library, causing those tests to
falsely fail.  Hilarity ensues.

Change-Id: Ic2536e8a652ef96e2a3923c1faa61f6c8c06bf58
Reviewed-on: https://code.wireshark.org/review/22417
Petri-Dish: Guy Harris <guy@alum.mit.edu>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Guy Harris <guy@alum.mit.edu>
(cherry picked from commit e61d2f624348329f8d73af55e6ff3e0e7ee012da)
Reviewed-on: https://code.wireshark.org/review/22418

2 files changed, 37 insertions, 1 deletions

diff --git a/acinclude.m4 b/acinclude.m4
index fcbbab8327..4ab5bcbdfb 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -495,18 +495,38 @@ AC_DEFUN([AC_WIRESHARK_ZLIB_CHECK],
 	then
 		#
 		# Well, we at least have the zlib header file.
+		#
 		# We link with zlib to support uncompression of
 		# gzipped network traffic, e.g. in an HTTP request
 		# or response body.
 		#
+		# Check for inflate() in zlib, to make sure the
+		# zlib library is usable.  For example, on at
+		# least some versions of Fedora, if you have a
+		# 64-bit machine, have both the 32-bit and 64-bit
+		# versions of the run-time zlib package installed,
+		# and have only the *32-bit* version of the zlib
+		# development package installed, it'll find the
+		# header, and think it can use zlib, and will use
+		# it in subsequent tests, but it'll try and link
+		# 64-bit test programs with the 32-bit library,
+		# causing those tests to falsely fail.  Hilarity
+		# ensues.
+		#
 		if test "x$zlib_dir" != "x"
 		then
 		  WS_CPPFLAGS="$WS_CPPFLAGS -I$zlib_dir/include"
 		  AC_WIRESHARK_ADD_DASH_L(WS_LDFLAGS, $zlib_dir/lib)
 		fi
-		LIBS="-lz $LIBS"
 		AC_DEFINE(HAVE_ZLIB, 1, [Define to use zlib library])
 		#
+		# Check for "inflate()" in zlib to make sure we can
+		# link with it.
+		#
+		AC_CHECK_LIB(z, inflate,,
+		    AC_MSG_ERROR([zlib.h found but linking with -lz failed to find inflate(); do you have the right developer package installed (32-bit vs. 64-bit)?]))
+
+		#
 		# Check for "inflatePrime()" in zlib, which we need
 		# in order to read compressed capture files.
 		#
diff --git a/cmake/modules/FindZLIB.cmake b/cmake/modules/FindZLIB.cmake
index ac4259b984..34fb1bb608 100644
--- a/cmake/modules/FindZLIB.cmake
+++ b/cmake/modules/FindZLIB.cmake
@@ -102,6 +102,22 @@ IF(WIN32)
 ELSE()
     INCLUDE(CheckFunctionExists)
     SET(CMAKE_REQUIRED_LIBRARIES ${ZLIB_LIBRARY})
+    #
+    # Check for inflate() in zlib, to make sure the zlib library is
+    # usable.
+    #
+    # For example, on at least some versions of Fedora, if you have a
+    # 64-bit machine, have both the 32-bit and 64-bit versions of the
+    # run-time zlib package installed, and have only the *32-bit*
+    # version of the zlib development package installed, it'll find the
+    # header, and think it can use zlib, and will use it in subsequent
+    # tests, but it'll try and link 64-bit test programs with the 32-bit
+    # library, causing those tests to falsely fail.  Hilarity ensues.
+    #
+    CHECK_FUNCTION_EXISTS("inflate" HAVE_INFLATE)
+    IF(NOT HAVE_INFLATE)
+        MESSAGE(FATAL_ERROR "zlib.h found but linking with -lz failed to find inflate(); do you have the right developer package installed (32-bit vs. 64-bit)?")
+    ENDIF()
     CHECK_FUNCTION_EXISTS("inflatePrime" HAVE_INFLATEPRIME)
     # reset
     SET(CMAKE_REQUIRED_LIBRARIES "")