rework to check cPath against nullptr only on !WNT

Change-Id: Iaca0d47b07f4b31b70ddeccb87f0f84019be81cd
Reviewed-on: https://gerrit.libreoffice.org/62055
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

xmlsecurity/source/dialogs/digitalsignaturesdialog.cxx

@@ -501,10 +501,10 @@ IMPL_STATIC_LINK(DigitalSignaturesDialog, CertMgrButtonHdl, Button*, pButton, vo
 #else
     const OUString aGUIServers[] = { OUString("kleopatra"), OUString("seahorse"),  OUString("gpa"), OUString("kgpg") };
     const char* cPath = getenv("PATH");
+    if (!cPath)
+        return;
 #endif
 
-    if (cPath)
-    {
     OUString aPath(cPath, strlen(cPath), osl_getThreadTextEncoding());
     OUString sFoundGUIServer, sExecutable;
 
@@ -536,7 +536,6 @@ IMPL_STATIC_LINK(DigitalSignaturesDialog, CertMgrButtonHdl, Button*, pButton, vo
                                                       XsResId(STR_XMLSECDLG_NO_CERT_MANAGER)));
         xInfoBox->run();
     }
-    }
 }
 
 IMPL_LINK_NOARG(DigitalSignaturesDialog, StartVerifySignatureHdl, LinkParamNone*, bool)