From b0c4ca9e088cbff5a5dbc5e95486397041a51d4a Mon Sep 17 00:00:00 2001
From: Caolán McNamara <caolanm@redhat.com>
Date: Wed, 11 Aug 2021 20:55:14 +0100
Subject: make --with-idlc-cpp=cpp work for gcc cpp as a ucpp replacement
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e.g. the example of
https://bugs.launchpad.net/ubuntu/+source/libreoffice/+bug/1524638
has the same output .urd using cpp with these flags as ucpp created

Change-Id: Iadfd2deba7d365c66c3260fd6736c031987e107c
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/120347
Tested-by: Jenkins
Tested-by: Caolán McNamara <caolanm@redhat.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
---
 idlc/Executable_idlc.mk     | 8 ++++++++
 idlc/source/idlccompile.cxx | 8 ++++++++
 2 files changed, 16 insertions(+)

(limited to 'idlc')

diff --git a/idlc/Executable_idlc.mk b/idlc/Executable_idlc.mk
index e194e9049c77..f2f79dcb8911 100644
--- a/idlc/Executable_idlc.mk
+++ b/idlc/Executable_idlc.mk
@@ -35,10 +35,18 @@ $(eval $(call gb_Executable_add_scanners,idlc,\
 ))
 
 ifneq (,$(SYSTEM_UCPP))
+
 $(eval $(call gb_Executable_add_defs,idlc,\
     -DSYSTEM_UCPP \
     -DUCPP=\"file://$(SYSTEM_UCPP)\" \
 ))
+
+ifneq ($(SYSTEM_UCPP_IS_GCC),)
+$(eval $(call gb_Executable_add_defs,idlc,\
+    -DSYSTEM_UCPP_IS_GCC \
+))
+endif
+
 endif
 
 $(eval $(call gb_Executable_add_exception_objects,idlc,\
diff --git a/idlc/source/idlccompile.cxx b/idlc/source/idlccompile.cxx
index bf3325d6821a..1902d63e0cad 100644
--- a/idlc/source/idlccompile.cxx
+++ b/idlc/source/idlccompile.cxx
@@ -237,7 +237,15 @@ sal_Int32 compileFile(const OString * pathname)
     ::std::vector< OUString> lCppArgs;
     lCppArgs.emplace_back("-DIDL");
     lCppArgs.emplace_back("-C");
+#ifdef SYSTEM_UCPP_IS_GCC
+    // -nostdinc Do not search the standard system directories for header files
+    lCppArgs.emplace_back("-nostdinc");
+    // with gcc cpp, even when not explicitly including anything, /usr/include/stdc-predef.h
+    // gets inserted without -nostdinc
+#else
+    // -zI Do not use the standard (compile-time) include path.
     lCppArgs.emplace_back("-zI");
+#endif
 
     Options* pOptions = idlc()->getOptions();
 
-- 
cgit