File cxx.patch of Package librsb

From: Jan Engelhardt <ej@inai.de>
Date: 2025-06-17 12:40:56.762725897 +0200

Don't wrap #include statements in extern "C".
This causes problems like

```
/usr/lib64/gcc/x86_64-suse-linux/15/include/omp.h:448:1: error: template with C linkage
  448 | template<typename __T, omp_allocator_handle_t __Handle>
rsb_common.h:32:1: note: ‘extern "C"’ linkage started here
   32 | extern "C" {
```

under at least gcc-15.

---
 rsb_common.h |   16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

Index: librsb-1.3.0.2/rsb_common.h
===================================================================
--- librsb-1.3.0.2.orig/rsb_common.h
+++ librsb-1.3.0.2/rsb_common.h
@@ -29,9 +29,6 @@ If not, see <http://www.gnu.org/licenses
 #define RSB_COMMON_H_INCLUDED
 
 #ifdef __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-#ifdef __cplusplus
 #define restrict	/* for now, the restrict keyword is not allowed in C++ */
 #endif  /* __cplusplus */
 /**
@@ -216,7 +213,13 @@ typedef int rsb_int;
 #if RSB_WANT_ACTION
 #define RSB_SHALL_QUIT ( rsb__quit_rsbench != 0 )
 #define RSB_INTERNALS_RSBENCH_HEAD_DECLS extern int rsb__quit_rsbench;
+#ifdef __cplusplus
+extern "C" {
+#endif
 void rsb__sigh(int signal);
+#ifdef __cplusplus
+}
+#endif
 #define RSB_SIGHR rsb__sigr();
 #else /* RSB_WANT_ACTION */
 #define RSB_SHALL_QUIT ( 0 != 0 )
@@ -1420,12 +1423,18 @@ struct rsb_optrace_t {
 #define RSB_MARF_EPS_NO_TEXT	(0x00000800)			/*!< #rsb_marf_t No text in EPS. */
 #define RSB_MARF_LATEX_RECURSION	(0x00001000)			/*!< #rsb_marf_t Matrix recursion as LaTeX. */
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 rsb_err_t rsb__adddir(rsb_char_t ** filenameap, rsb_int_t * filenamenp, const rsb_char_t * matrixpath, rsb_flags_t faflags);
 void rsb__setenv(const rsb_char_t * var_val);
 rsb_real_t rsb__getenv_real_t(const char*envv, const rsb_real_t altv);
 rsb_int_t rsb__getenv_int_t(const char*envv, const rsb_int_t altv);
 const rsb_char_t * rsb__getenv_str(const char*envv, const rsb_char_t* altv);
 rsb_char_t rsb__getenv_char(const char *envv, const rsb_char_t altv);
+#ifdef __cplusplus
+}
+#endif
 
 #ifdef RSB_HAVE_ASSERT_H 
 #ifdef RSB_USE_ASSERT
@@ -1510,7 +1519,6 @@ rsb_char_t rsb__getenv_char(const char *
 #include "rsb_tune.h"		/* */
 
 #ifdef __cplusplus
-}
 #endif  /* __cplusplus */
 
 #endif /* RSB_COMMON_H_INCLUDED */