From afda967b07745c16d8c4a2a649a2709b0f8183e4 Mon Sep 17 00:00:00 2001
From: Jose Luis Blanco-Claraco <joseluisblancoc@gmail.com>
Date: Thu, 10 Aug 2023 09:43:06 +0200
Subject: [PATCH] Fix C linkage build error in CSparse

---
 doc/source/doxygen-docs/changelog.md        |  3 ++-
 libs/math/include/mrpt/math/CSparseMatrix.h | 10 +++-------
 2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/doc/source/doxygen-docs/changelog.md b/doc/source/doxygen-docs/changelog.md
index 697d66f255..5fbdc117a7 100644
--- a/doc/source/doxygen-docs/changelog.md
+++ b/doc/source/doxygen-docs/changelog.md
@@ -1,7 +1,8 @@
 \page changelog Change Log
 
 # Version 2.10.2: UNRELEASED
-(No changes yet)
+- BUG FIXES:
+  - Fix CSparse "C" linkage build error (OSX Clang)
 
 # Version 2.10.1: Released August 10th, 2023
 - Build system:
diff --git a/libs/math/include/mrpt/math/CSparseMatrix.h b/libs/math/include/mrpt/math/CSparseMatrix.h
index 43609454e6..4d6467e369 100644
--- a/libs/math/include/mrpt/math/CSparseMatrix.h
+++ b/libs/math/include/mrpt/math/CSparseMatrix.h
@@ -19,18 +19,14 @@
 #include <stdexcept>
 
 // Include CSparse lib headers, either from the system or embedded:
-extern "C"
-{
 #if MRPT_HAS_SUITESPARSE
-#define NCOMPLEX  // In MRPT we don't need complex numbers, so avoid the
-// annoying warning: 'cs_ci_house' has C-linkage specified,
-// but returns UDT 'std::complex<double>' which is
-// incompatible with C
 #include "cs.h"
 #else
+extern "C"
+{
 #include <mrpt/3rdparty/CSparse/cs.h>
-#endif
 }
+#endif
 
 namespace mrpt::math
 {