Use relative directory to locate PROJ resource files.

Fixes #1490

This is an extension of the Window-specific logic added recently to
Unix builds. This reuses parts of proposed past commit
https://github.com/OSGeo/PROJ/pull/1517/commits/82a07e51c6e24ddb936d131ababe29f1ac36ef14
(credits to @abellgithub)

1 files changed, 6 insertions, 1 deletions

diff --git a/src/apps/projsync.cpp b/src/apps/projsync.cpp
index 40848f51..61681260 100644
--- a/src/apps/projsync.cpp
+++ b/src/apps/projsync.cpp
@@ -137,7 +137,12 @@ int main(int argc, char *argv[]) {
         } else if (arg == "--user-writable-directory") {
             // do nothing
         } else if (arg == "--system-directory") {
-            targetDir = PROJ_LIB;
+            targetDir = pj_get_relative_share_proj(ctx);
+#ifdef PROJ_LIB
+            if (targetDir.empty()) {
+                targetDir = PROJ_LIB;
+            }
+#endif
         } else if (arg == "--target-dir" && i + 1 < argc) {
             i++;
             targetDir = argv[i];