net-libs/libssh: Set -DWITH_STACK_PROTECTOR=OFF

The build system injects -fstack-protector _after_ CFLAGS, which means
that when CFLAGS define a stronger SSP, this lowers its protection
instead of improving it.

Additionally, the test for the compiler flag succeeds on HPPA when it
shouldn't, causing the build to fail later on:

In file included from src/agent.c:53:0:
include/libssh/priv.h:169:4: error: #error "Your system must provide a __func__ macro"

Bug: https://bugs.gentoo.org/59506
Package-Manager: Portage-2.3.48, Repoman-2.3.10

net-libs/libssh/libssh-0.7.4.ebuild

@@ -64,6 +64,7 @@ multilib_src_configure() {
 		-DWITH_SERVER="$(usex server)"
 		-DWITH_SFTP="$(usex sftp)"
 		-DWITH_SSH1="$(usex ssh1)"
+		-DWITH_STACK_PROTECTOR=OFF
 		-DWITH_STATIC_LIB="$(usex static-libs)"
 		-DWITH_STATIC_LIB="$(usex test)"
 		-DWITH_TESTING="$(usex test)"

net-libs/libssh/libssh-0.7.5-r2.ebuild

@@ -67,6 +67,7 @@ multilib_src_configure() {
 		-DWITH_SERVER="$(usex server)"
 		-DWITH_SFTP="$(usex sftp)"
 		-DWITH_SSH1="$(usex ssh1)"
+		-DWITH_STACK_PROTECTOR=OFF
 		-DWITH_STATIC_LIB="$(usex static-libs)"
 		-DWITH_STATIC_LIB="$(usex test)"
 		-DWITH_TESTING="$(usex test)"

net-libs/libssh/libssh-0.8.1.ebuild

@@ -76,6 +76,7 @@ multilib_src_configure() {
 		-DWITH_PCAP="$(usex pcap)"
 		-DWITH_SERVER="$(usex server)"
 		-DWITH_SFTP="$(usex sftp)"
+		-DWITH_STACK_PROTECTOR=OFF
 		-DWITH_STATIC_LIB="$(usex static-libs)"
 		-DWITH_STATIC_LIB="$(usex test)"
 		-DWITH_ZLIB="$(usex zlib)"

net-libs/libssh/libssh-9999.ebuild

@@ -76,6 +76,7 @@ multilib_src_configure() {
 		-DWITH_PCAP="$(usex pcap)"
 		-DWITH_SERVER="$(usex server)"
 		-DWITH_SFTP="$(usex sftp)"
+		-DWITH_STACK_PROTECTOR=OFF
 		-DWITH_STATIC_LIB="$(usex static-libs)"
 		-DWITH_STATIC_LIB="$(usex test)"
 		-DWITH_ZLIB="$(usex zlib)"