ncurses: Prevent LDFLAGS being emitted in .pc files

By default ncurses includes the values of LDFLAGS in its output
pkgconfig .pc files. This causes issues because OE includes options that
are specific to either the build host, or build configuration. These
options are not expected to be embedded in the pkgconfig output that is
installed.

Specifically this change resolves issues with uninative, where uninative
includes '-Wl,--dynamic-linker=' in LDFLAGS in order to force the
building and execution of native binaries against the dynamic linker
provided by uninative. This path is specific to TMPDIR at the time of
build, such that the installed files (and the associated sstate) have
this path. This prevents the sstate from being portable across build
directories/hosts.

(From OE-Core rev: ef960d14bd9cecb9a3b50994636fbd455f06104a)

Signed-off-by: Nathan Rossi <nathan@nathanrossi.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/ncurses/files/0003-gen-pkgconfig.in-Do-not-include-LDFLAGS-in-generated.patch

@@ -0,0 +1,29 @@
+From 3b3e87934bb6d8511261d7c3d6e39b4f71849272 Mon Sep 17 00:00:00 2001
+From: Nathan Rossi <nathan@nathanrossi.com>
+Date: Mon, 14 Dec 2020 13:39:02 +1000
+Subject: [PATCH] gen-pkgconfig.in: Do not include LDFLAGS in generated pc
+ files
+
+Including the LDFLAGS in the pkgconfig output is problematic as OE
+includes build host specific paths and options (e.g. uninative and
+'-Wl,--dynamic-linker=').
+
+Upstream-Status: Inappropriate [OE Specific]
+Signed-off-by: Nathan Rossi <nathan@nathanrossi.com>
+---
+ misc/gen-pkgconfig.in | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/misc/gen-pkgconfig.in b/misc/gen-pkgconfig.in
+index 8f00b824b9..009d215663 100644
+--- a/misc/gen-pkgconfig.in
++++ b/misc/gen-pkgconfig.in
+@@ -80,7 +80,7 @@ if [ "$includedir" != "/usr/include" ]; then
+ fi
+ 
+ lib_flags=
+-for opt in -L$libdir @LDFLAGS@ @EXTRA_LDFLAGS@ @LIBS@
++for opt in -L$libdir @LIBS@
+ do
+ 	case $opt in
+ 	-l*) # LIBS is handled specially below

meta/recipes-core/ncurses/ncurses_6.2.bb

@@ -2,6 +2,7 @@ require ncurses.inc
 
 SRC_URI += "file://0001-tic-hang.patch \
            file://0002-configure-reproducible.patch \
+           file://0003-gen-pkgconfig.in-Do-not-include-LDFLAGS-in-generated.patch \
            "
 # commit id corresponds to the revision in package version
 SRCREV = "a669013cd5e9d6434e5301348ea51baf306c93c4"