diff --git a/config/find_system_library.m4 b/config/find_system_library.m4
index 3f2f7b709f0e..9a95d6a15033 100644
--- a/config/find_system_library.m4
+++ b/config/find_system_library.m4
@@ -1,77 +1,93 @@
 # find_system_lib.m4 - Macros to search for a system library.   -*- Autoconf -*-
 
 dnl requires pkg.m4 from pkg-config
 dnl requires ax_save_flags.m4 from autoconf-archive
 dnl requires ax_restore_flags.m4 from autoconf-archive
 
-dnl FIND_SYSTEM_LIBRARY(VARIABLE-PREFIX, MODULE, HEADER, HEADER-PREFIXES, LIBRARY, FUNCTIONS, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
+dnl ZFS_AC_FIND_SYSTEM_LIBRARY(VARIABLE-PREFIX, MODULE, HEADER, HEADER-PREFIXES, LIBRARY, FUNCTIONS, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
 
-AC_DEFUN([FIND_SYSTEM_LIBRARY], [
+AC_DEFUN([ZFS_AC_FIND_SYSTEM_LIBRARY], [
     AC_REQUIRE([PKG_PROG_PKG_CONFIG])
 
+    _header_found=
     _library_found=
 
-    AS_IF([test -n "$2"], [PKG_CHECK_MODULES([$1], [$2], [_library_found=1], [:])])
+    AS_IF([test -n "$2"], [PKG_CHECK_MODULES([$1], [$2], [
+	_header_found=1
+	_library_found=1
+    ], [:])])
 
-    AS_IF([test -z "$_library_found"], [
-        AS_IF([test -f /usr/include/[$3]], [
-            AC_SUBST([$1][_CFLAGS], [])
-            AC_SUBST([$1][_LIBS], ["-l[$5]]")
-            _library_found=1
-        ],[ AS_IF([test -f /usr/local/include/[$3]], [
-            AC_SUBST([$1][_CFLAGS], ["-I/usr/local/include"])
-            AC_SUBST([$1][_LIBS], ["-L/usr/local -l[$5]]")
-            _library_found=1
-        ],[dnl ELSE
-	    :
-            m4_foreach([prefix], [$4], [
-                AS_IF([test "x$_library_found" != "x1"], [
-                    AS_IF([test -f [/usr/include/]prefix[/][$3]], [
-                        AC_SUBST([$1][_CFLAGS], ["[-I/usr/include/]prefix["]])
-                        AC_SUBST([$1][_LIBS], ["-l[$5]]")
-                        _library_found=1
-                    ],[ AS_IF([test -f [/usr/local/include/]prefix[/][$3]], [
-                        AC_SUBST([$1][_CFLAGS], ["[-I/usr/local/include/]prefix["]])
-                        AC_SUBST([$1][_LIBS], ["-L/usr/local -l[$5]"])
-                        _library_found=1
-                    ])])
-                ])
-            ])
-        ])])
+    # set _header_found/_library_found if the user passed in CFLAGS/LIBS
+    AS_IF([test "x$[$1][_CFLAGS]" != x], [_header_found=1])
+    AS_IF([test "x$[$1][_LIBS]" != x], [_library_found=1])
 
-        AS_IF([test -z "$_library_found"], [
-            AC_MSG_WARN([cannot find [$5] via pkg-config or in the standard locations])
-        ])
-    ])
+    AX_SAVE_FLAGS
 
-    dnl do some further sanity checks
+    orig_CFLAGS="$CFLAGS"
 
-    AS_IF([test -n "$_library_found"], [
-        AX_SAVE_FLAGS
+    for _prefixdir in /usr /usr/local
+    do
+	AS_VAR_PUSHDEF([header_cache], [ac_cv_header_$3])
+	AS_IF([test "x$_prefixdir" != "x/usr"], [
+	    [$1][_CFLAGS]="-I$lt_sysroot$_prefixdir/include"
+	    AS_IF([test "x$_library_found" = x], [
+		[$1][_LIBS]="-L$lt_sysroot$_prefixdir/lib"
+	    ])
+	])
+	CFLAGS="$orig_CFLAGS $[$1][_CFLAGS]"
+	AS_UNSET([header_cache])
+	AC_CHECK_HEADER([$3], [
+	    _header_found=1
+	    break
+	], [AS_IF([test "x$_header_found" = "x1"], [
+	    # if pkg-config or the user set CFLAGS, fail if the header is unusable
+	    AC_MSG_FAILURE([header [$3] for library [$5] is not usable])
+	])], [AC_INCLUDES_DEFAULT])
+	# search for header under HEADER-PREFIXES
+	m4_foreach_w([prefix], [$4], [
+	    [$1][_CFLAGS]=["-I$lt_sysroot$_prefixdir/include/]prefix["]
+	    CFLAGS="$orig_CFLAGS $[$1][_CFLAGS]"
+	    AS_UNSET([header_cache])
+	    AC_CHECK_HEADER([$3], [
+		_header_found=1
+		break
+	    ], [], [AC_INCLUDES_DEFAULT])
+	])
+	AS_VAR_POPDEF([header_cache])
+    done
 
-        CPPFLAGS="$CPPFLAGS $(echo $[$1][_CFLAGS] | sed 's/-include */-include-/g; s/^/ /; s/ [^-][^ ]*//g; s/ -[^Ii][^ ]*//g; s/-include-/-include /g; s/^ //;')"
-        CFLAGS="$CFLAGS $[$1][_CFLAGS]"
-        LDFLAGS="$LDFLAGS $[$1][_LIBS]"
+    AS_IF([test "x$_header_found" = "x1"], [
+	AS_IF([test "x$_library_found" = x], [
+	    [$1][_LIBS]="$[$1]_LIBS -l[$5]"
+	])
+	LDFLAGS="$LDFLAGS $[$1][_LIBS]"
 
-        AC_CHECK_HEADER([$3], [], [
-            AC_MSG_WARN([header [$3] for library [$5] is not usable])
-            _library_found=
-        ])
+	_libcheck=1
+	m4_ifval([$6],
+	    [m4_foreach_w([func], [$6], [AC_CHECK_LIB([$5], func, [:], [_libcheck=])])],
+	    [AC_CHECK_LIB([$5], [main], [:], [_libcheck=])])
 
-        m4_foreach([func], [$6], [
-            AC_CHECK_LIB([$5], func, [], [
-                AC_MSG_WARN([cannot find ]func[ in library [$5]])
-                _library_found=
-            ])
-        ])
-        
-        AX_RESTORE_FLAGS
+	AS_IF([test "x$_libcheck" = "x1"], [_library_found=1],
+	    [test "x$_library_found" = "x1"], [
+	    # if pkg-config or the user set LIBS, fail if the library is unusable
+	    AC_MSG_FAILURE([library [$5] is not usable])
+	])
+    ], [test "x$_library_found" = "x1"], [
+	# if the user set LIBS, fail if we didn't find the header
+	AC_MSG_FAILURE([cannot find header [$3] for library [$5]])
     ])
 
-    AS_IF([test -n "$_library_found"], [
-        AC_DEFINE([HAVE_][$1], [1], [Define if you have [$5]])
-        :;$7
+    AX_RESTORE_FLAGS
+
+    AS_IF([test "x$_header_found" = "x1" && test "x$_library_found" = "x1"], [
+	AC_SUBST([$1]_CFLAGS)
+	AC_SUBST([$1]_LIBS)
+	AC_DEFINE([HAVE_][$1], [1], [Define if you have [$5]])
+	$7
     ],[dnl ELSE
-        :;$8
+	AC_SUBST([$1]_CFLAGS, [])
+	AC_SUBST([$1]_LIBS, [])
+	AC_MSG_WARN([cannot find [$5] via pkg-config or in the standard locations])
+	$8
     ])
 ])
diff --git a/config/user-libaio.m4 b/config/user-libaio.m4
index 0a58876fec35..95c144d76b4f 100644
--- a/config/user-libaio.m4
+++ b/config/user-libaio.m4
@@ -1,6 +1,6 @@
 dnl #
 dnl # Check for libaio - only used for libaiot test cases.
 dnl #
 AC_DEFUN([ZFS_AC_CONFIG_USER_LIBAIO], [
-	FIND_SYSTEM_LIBRARY(LIBAIO, [], [libaio.h], [], [aio], [], [user_libaio=yes], [user_libaio=no])
+	ZFS_AC_FIND_SYSTEM_LIBRARY(LIBAIO, [], [libaio.h], [], [aio], [], [user_libaio=yes], [user_libaio=no])
 ])
diff --git a/config/user-libblkid.m4 b/config/user-libblkid.m4
index 427c4f172c91..f2016dcb15cd 100644
--- a/config/user-libblkid.m4
+++ b/config/user-libblkid.m4
@@ -1,9 +1,9 @@
 dnl #
 dnl # Check for libblkid.  Basic support for detecting ZFS pools
 dnl # has existing in blkid since 2008.
 dnl #
 AC_DEFUN([ZFS_AC_CONFIG_USER_LIBBLKID], [
-	FIND_SYSTEM_LIBRARY(LIBBLKID, [blkid], [blkid/blkid.h], [], [blkid], [], [], [
+	ZFS_AC_FIND_SYSTEM_LIBRARY(LIBBLKID, [blkid], [blkid/blkid.h], [], [blkid], [], [], [
 		AC_MSG_FAILURE([
 		*** blkid.h missing, libblkid-devel package required])])
 ])
diff --git a/config/user-libcrypto.m4 b/config/user-libcrypto.m4
index 432b848385ff..7293e1b0b42c 100644
--- a/config/user-libcrypto.m4
+++ b/config/user-libcrypto.m4
@@ -1,8 +1,8 @@
 dnl #
 dnl # Check for libcrypto. Used for userspace password derivation via PBKDF2.
 dnl #
 AC_DEFUN([ZFS_AC_CONFIG_USER_LIBCRYPTO], [
-	FIND_SYSTEM_LIBRARY(LIBCRYPTO, [libcrypto], [openssl/evp.h], [], [crypto], [PKCS5_PBKDF2_HMAC_SHA1], [], [
+	ZFS_AC_FIND_SYSTEM_LIBRARY(LIBCRYPTO, [libcrypto], [openssl/evp.h], [], [crypto], [PKCS5_PBKDF2_HMAC_SHA1], [], [
 		AC_MSG_FAILURE([
 		*** evp.h missing, libssl-devel package required])])
 ])
diff --git a/config/user-libtirpc.m4 b/config/user-libtirpc.m4
index 19c02c9d5468..aa7ab4a1fd32 100644
--- a/config/user-libtirpc.m4
+++ b/config/user-libtirpc.m4
@@ -1,30 +1,30 @@
 dnl #
 dnl # Check for libtirpc - may be needed for xdr functionality
 dnl #
 AC_DEFUN([ZFS_AC_CONFIG_USER_LIBTIRPC], [
 	AC_ARG_WITH([tirpc],
 	    [AS_HELP_STRING([--with-tirpc],
 		[use tirpc for xdr encoding @<:@default=check@:>@])],
 	    [],
 	    [with_tirpc=check])
 
 	have_xdr=
 
         AS_IF([test "x$with_tirpc" != "xyes"], [
 	    AC_SEARCH_LIBS([xdrmem_create], [], [have_xdr=1], [
 		AS_IF([test "x$with_tirpc" = "xno"], [
 		    AC_MSG_FAILURE([xdrmem_create() requires sunrpc support in libc if not using libtirpc])
 		])
 	    ])
         ])
 
 	AS_IF([test "x$have_xdr" = "x"], [
-            FIND_SYSTEM_LIBRARY(LIBTIRPC, [libtirpc], [rpc/xdr.h], [tirpc], [tirpc], [xdrmem_create], [], [
+            ZFS_AC_FIND_SYSTEM_LIBRARY(LIBTIRPC, [libtirpc], [rpc/xdr.h], [tirpc], [tirpc], [xdrmem_create], [], [
 		AS_IF([test "x$with_tirpc" = "xyes"], [
 		    AC_MSG_FAILURE([--with-tirpc was given, but libtirpc is not available, try installing libtirpc-devel])
 		],[dnl ELSE
 		    AC_MSG_FAILURE([neither libc sunrpc support nor libtirpc is available, try installing libtirpc-devel])
 		])
 	    ])
 	])
 ])
diff --git a/config/user-libudev.m4 b/config/user-libudev.m4
index 5164d17cdcff..8c3c1d7e0087 100644
--- a/config/user-libudev.m4
+++ b/config/user-libudev.m4
@@ -1,19 +1,17 @@
 dnl #
 dnl # Check for libudev - needed for vdev auto-online and auto-replace
 dnl #
 AC_DEFUN([ZFS_AC_CONFIG_USER_LIBUDEV], [
-	FIND_SYSTEM_LIBRARY(LIBUDEV, [libudev], [libudev.h], [], [udev], [], [user_libudev=yes], [user_libudev=no])
+	ZFS_AC_FIND_SYSTEM_LIBRARY(LIBUDEV, [libudev], [libudev.h], [], [udev], [], [user_libudev=yes], [user_libudev=no])
 
 	AS_IF([test "x$user_libudev" = xyes], [
 	    AX_SAVE_FLAGS
 
 	    CFLAGS="$CFLAGS $LIBUDEV_CFLAGS"
-	    LDFLAGS="$LDFLAGS $LIBUDEV_LIBS"
+	    LIBS="$LIBUDEV_LIBS $LIBS"
 
-	    AC_CHECK_LIB([udev], [udev_device_get_is_initialized], [
-	        AC_DEFINE([HAVE_LIBUDEV_UDEV_DEVICE_GET_IS_INITIALIZED], 1, [
-	        Define if udev_device_get_is_initialized is available])], [])
+	    AC_CHECK_FUNCS([udev_device_get_is_initialized])
 
 	    AX_RESTORE_FLAGS
 	])
 ])
diff --git a/config/user-libuuid.m4 b/config/user-libuuid.m4
index c4012f30ab27..0cfa83c9926a 100644
--- a/config/user-libuuid.m4
+++ b/config/user-libuuid.m4
@@ -1,8 +1,8 @@
 dnl #
 dnl # Check for libuuid
 dnl #
 AC_DEFUN([ZFS_AC_CONFIG_USER_LIBUUID], [
-	FIND_SYSTEM_LIBRARY(LIBUUID, [uuid], [uuid/uuid.h], [], [uuid], [uuid_generate, uuid_is_null], [], [
+	ZFS_AC_FIND_SYSTEM_LIBRARY(LIBUUID, [uuid], [uuid/uuid.h], [], [uuid], [uuid_generate uuid_is_null], [], [
 	    AC_MSG_FAILURE([*** libuuid-devel package required])
 	])
 ])
diff --git a/config/user-zlib.m4 b/config/user-zlib.m4
index d30fde288820..1f3792829bb6 100644
--- a/config/user-zlib.m4
+++ b/config/user-zlib.m4
@@ -1,8 +1,8 @@
 dnl #
 dnl # Check for zlib
 dnl #
 AC_DEFUN([ZFS_AC_CONFIG_USER_ZLIB], [
-	FIND_SYSTEM_LIBRARY(ZLIB, [zlib], [zlib.h], [], [z], [compress2, uncompress, crc32], [], [
+	ZFS_AC_FIND_SYSTEM_LIBRARY(ZLIB, [zlib], [zlib.h], [], [z], [compress2 uncompress crc32], [], [
 	    AC_MSG_FAILURE([*** zlib-devel package required])
 	])
 ])