package/libmodsecurity: fix static build

Fix the following static build failure with nginx raised since bump of
libmodsecurity to version 3.0.5 in commit
464d0be380c84ac7c3f1684e49153c3868280d7e:

/home/buildroot/autobuild/instance-2/output-1/host/lib/gcc/xtensa-buildroot-linux-uclibc/10.3.0/../../../../xtensa-buildroot-linux-uclibc/bin/ld: /home/buildroot/autobuild/instance-2/output-1/host/bin/../xtensa-buildroot-linux-uclibc/sysroot/usr/lib/libmodsecurity.a(libmodsecurity_la-transaction.o): in function `std::basic_streambuf<char, std::char_traits<char> >::sbumpc() [clone .isra.0]':
transaction.cc:(.text+0x40): undefined reference to `std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_dispose()'

Fixes:
 - http://autobuild.buildroot.org/results/e5a9eb8448980f1c5cafe97180b7d1f48ddf02ca

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/libmodsecurity/0002-modsecurity.pc.in-add-lstdc.patch

@@ -0,0 +1,32 @@
+From 1a84881b280eb08852d5495c57e44351a40d3f91 Mon Sep 17 00:00:00 2001
+From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+Date: Mon, 26 Jul 2021 00:24:57 +0200
+Subject: [PATCH] modsecurity.pc.in: add -lstdc++
+
+Add -lstdc++ to Libs.Private to avoid the following static build failure
+with nginx:
+
+/home/buildroot/autobuild/instance-2/output-1/host/lib/gcc/xtensa-buildroot-linux-uclibc/10.3.0/../../../../xtensa-buildroot-linux-uclibc/bin/ld: /home/buildroot/autobuild/instance-2/output-1/host/bin/../xtensa-buildroot-linux-uclibc/sysroot/usr/lib/libmodsecurity.a(libmodsecurity_la-transaction.o): in function `std::basic_streambuf<char, std::char_traits<char> >::sbumpc() [clone .isra.0]':
+transaction.cc:(.text+0x40): undefined reference to `std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_dispose()'
+
+Fixes:
+ - http://autobuild.buildroot.org/results/e5a9eb8448980f1c5cafe97180b7d1f48ddf02ca
+
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ modsecurity.pc.in | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/modsecurity.pc.in b/modsecurity.pc.in
+index 96cdf5ca..7c895ddc 100644
+--- a/modsecurity.pc.in
++++ b/modsecurity.pc.in
+@@ -8,4 +8,4 @@ Description: ModSecurity API
+ Version: @MSC_VERSION_WITH_PATCHLEVEL@
+ Cflags: -I@includedir@
+ Libs: -L@libdir@ -lmodsecurity
+-Libs.private: @CURL_LDADD@ @GEOIP_LDADD@ @MAXMIND_LDADD@ @GLOBAL_LDADD@ @LIBXML2_LDADD@ @LMDB_LDADD@ @LUA_LDADD@ @PCRE_LDADD@ @SSDEEP_LDADD@ @YAJL_LDADD@
++Libs.private: @CURL_LDADD@ @GEOIP_LDADD@ @MAXMIND_LDADD@ @GLOBAL_LDADD@ @LIBXML2_LDADD@ @LMDB_LDADD@ @LUA_LDADD@ @PCRE_LDADD@ @SSDEEP_LDADD@ @YAJL_LDADD@ -lstdc++
+-- 
+2.30.2
+