Probably known reporting it anyway.
Same issues in three files related to unit tests.
Try const char * or strdup.
In file included from /src/inchi/INCHI-1-TEST/tests/test_unit/test_ichiprt1.cpp:13:
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8062:13: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8062 | ITRACE_("\n\n*********************************************************************\n* Subgraf:");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8063:13: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8063 | ITRACE_("\n\tNodes: %-d ( ", sg->nnodes);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8066:17: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8066 | ITRACE_("%-d ", sg->nodes[p]);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8068:13: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8068 | ITRACE_(")\n\tAdj lists:\n");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8071:17: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8071 | ITRACE_("\tNode #%-d (orig# %-d) ::: Neighbors (node#, orig#) : ",
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8076:21: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8076 | ITRACE_("(%-d/%-d/%-d) ", nbr, sg->nodes[nbr]);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8078:17: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8078 | ITRACE_("\n");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8080:13: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8080 | ITRACE_("\n* End Subgraf\n*********************************************************************\n");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8184:21: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8184 | ITRACE_("\n\tFound path (in orig atom numbers):\t");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8188:25: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8188 | ITRACE_("%-d ", orig_atnum);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8194:21: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8194 | ITRACE_("\t( In node nums: ");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8201:25: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8201 | ITRACE_("%-d ", spf->seen[k]);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8203:21: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8203 | ITRACE_(")");
| ^
13 warnings generated.
In file included from /src/inchi/INCHI-1-TEST/tests/test_unit/test_ichiprt1_enhancedStereo.cpp:13:
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8062:13: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8062 | ITRACE_("\n\n*********************************************************************\n* Subgraf:");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8063:13: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8063 | ITRACE_("\n\tNodes: %-d ( ", sg->nnodes);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8066:17: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8066 | ITRACE_("%-d ", sg->nodes[p]);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8068:13: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8068 | ITRACE_(")\n\tAdj lists:\n");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8071:17: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8071 | ITRACE_("\tNode #%-d (orig# %-d) ::: Neighbors (node#, orig#) : ",
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8076:21: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8076 | ITRACE_("(%-d/%-d/%-d) ", nbr, sg->nodes[nbr]);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8078:17: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8078 | ITRACE_("\n");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8080:13: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8080 | ITRACE_("\n* End Subgraf\n*********************************************************************\n");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8184:21: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8184 | ITRACE_("\n\tFound path (in orig atom numbers):\t");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8188:25: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8188 | ITRACE_("%-d ", orig_atnum);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8194:21: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8194 | ITRACE_("\t( In node nums: ");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8201:25: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8201 | ITRACE_("%-d ", spf->seen[k]);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8203:21: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8203 | ITRACE_(")");
| ^
13 warnings generated.
In file included from /src/inchi/INCHI-1-TEST/tests/test_unit/test_ichiprt3.cpp:7:
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8062:13: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8062 | ITRACE_("\n\n*********************************************************************\n* Subgraf:");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8063:13: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8063 | ITRACE_("\n\tNodes: %-d ( ", sg->nnodes);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8066:17: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8066 | ITRACE_("%-d ", sg->nodes[p]);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8068:13: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8068 | ITRACE_(")\n\tAdj lists:\n");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8071:17: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8071 | ITRACE_("\tNode #%-d (orig# %-d) ::: Neighbors (node#, orig#) : ",
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8076:21: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8076 | ITRACE_("(%-d/%-d/%-d) ", nbr, sg->nodes[nbr]);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8078:17: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8078 | ITRACE_("\n");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8080:13: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8080 | ITRACE_("\n* End Subgraf\n*********************************************************************\n");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8184:21: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8184 | ITRACE_("\n\tFound path (in orig atom numbers):\t");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8188:25: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8188 | ITRACE_("%-d ", orig_atnum);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8194:21: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8194 | ITRACE_("\t( In node nums: ");
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8201:25: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8201 | ITRACE_("%-d ", spf->seen[k]);
| ^
/src/inchi/INCHI-1-TEST/tests/test_unit/../../../INCHI-1-SRC/INCHI_BASE/src/strutil.c:8203:21: warning: ISO C++11 does not allow conversion from string literal to 'char *'
[-Wwritable-strings]
8203 | ITRACE_(")");
| ^
13 warnings generated.
Probably known reporting it anyway.
Same issues in three files related to unit tests.
Try
const char *orstrdup.