package/exim: remove libnsl linking with Glibc.

glibc now considers its built-in libnsl as being obsolete, and requires passing --enable-obsolete-libnsl to have it built and installed. libnsl is now provided as a separate project [1], but it isn't packaged yet in Buildroot.

In preparation for dropping --enable-obsolete-libnsl from the glibc package, this commit ensures that exim doesn't use libnsl. It was already the case for uclibc and musl toolchains, so this commit simply extends that to make sure libnsl is also not used with glibc toolchains.

Only Exim's nis.so and nisplus.so lookup modules require libnsl, but they are not build by default. So we can safely remove -lnsl from the Makefile-Linux. If someone want these modules, a new libnsl package must be added first to provide nsl library.

Note: Fedora 28 has switched to the new libnsl library that bring IPV6 support. [2]

[1] https://github.com/thkukuk/libnsl.git
[2] https://fedoraproject.org/wiki/Changes/NISIPv6

---
 package/exim/exim.mk | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

index 37eab501a4..586bf3235c 100644
@@ -72,13 +72,15 @@ define EXIM_USE_DEFAULT_CONFIG_FILE_OPENSSL
 endef
 endif
 
-# only glibc provides libnsl, remove -lnsl for all other toolchains
+# Only Exim's nis.so and nisplus.so lookup modules require libnsl,
+# but they are not build by default.
+# libnsl has been deprecated from Glibc and no other libc provide it.
+# There is no libnsl package in Buildroot yet.
+# Remove -lnsl for all toolchains.
 # http://bugs.exim.org/show_bug.cgi?id=1564
-ifeq ($(BR2_TOOLCHAIN_USES_GLIBC),)
 define EXIM_REMOVE_LIBNSL_FROM_MAKEFILE
 	$(SED) 's/-lnsl//g' $(@D)/OS/Makefile-Linux
 endef
-endif
 
 # musl does not provide struct ip_options nor struct ip_opts (but it is
 # available with both glibc and uClibc)

2.14.3

libnsl from Glibc is deprecated and should not be used anymore. Remove libnsl.so.* from GLIBC_LIBS_LIB.

libnsl is now an separate library that can be packaged later if necessary [1].

Note: libnsl from Glibc doesn't build with gcc 8 due new warning [2].

[1] https://github.com/thkukuk/libnsl.git
[2] http://patchwork.sourceware.org/patch/26437

This reverts commit 398747f5fafca8c07e696612d8eded53d4f935c7.

---
v2: remove libnsl.so.* from GLIBC_LIBS_LIB

---
 package/glibc/glibc.mk | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

index 3ab673c0cc..c1c5ac687f 100644
@@ -100,7 +100,6 @@ define GLIBC_CONFIGURE_CMDS
 		--disable-profile \
 		--without-gd \
 		--enable-obsolete-rpc \
-		--enable-obsolete-nsl \
 		--enable-kernel=$(call qstrip,$(BR2_TOOLCHAIN_HEADERS_AT_LEAST)) \
 		--with-headers=$(STAGING_DIR)/usr/include)
 	$(GLIBC_ADD_MISSING_STUB_H)

@@ -113,7 +112,7 @@ endef
 
 GLIBC_LIBS_LIB = \
 	ld*.so.* libanl.so.* libc.so.* libcrypt.so.* libdl.so.* libgcc_s.so.* \
-	libm.so.* libnsl.so.* libpthread.so.* libresolv.so.* librt.so.* \
+	libm.so.* libpthread.so.* libresolv.so.* librt.so.* \
 	libutil.so.* libnss_files.so.* libnss_dns.so.* libmvec.so.*
 
 ifeq ($(BR2_PACKAGE_GDB),y)

2.14.3

Hi Romain,

...and this triggered host toolchain issues such as:

http://autobuild.buildroot.net/results/a362dfef9e5187931431000c54f03f841d17c847/

The reason is that the host tools generates by exim (namely buildconfig) are built out of build-br/Makefile, which is assembled by concatenating together several makefiles including OS/Makefile-Linux. So the buildconfig tool will try to link against libnsl, but that's not needed.

As a positive side effect, this patch fixes the above issue.

Luca

Hi Romain,

As discussed, I suggest the following changes to the log message. Feel free to improve them.

Subject:

+package/exim: remove libnsl linking with Glibc. -package/exim: remove libnsl linking and fix native tools build

Remove from description:

Note: Fedora 28 has switched to the new libnsl library that bring IPV6 support. [2]

Add to description:

This also fixes the following build error on recent distributions where libnsl is not installed (e.g. Fedora 28 which has switched to the new libnsl library that brings IPV6 support. [2]):

/bin/sh ../scripts/Configure-os.c
/usr/bin/gcc buildconfig.c
/usr/bin/ld: cannot find -lnsl
collect2: error: ld returned 1 exit status

This happens while exim builds a host tool named buildconfig. The build is done in build-br/Makefile, which in turn is assembled by concatenating together several makefiles, including OS/Makefile-Linux. So the buildconfig tool will be built with the same $(LIBS) as the target executables, including -lnsl. Removing -lnsl also fixes building buildconfig since it does not need libnsl.

Bye,

Luca