[1.5] introduce fix for the SOVERSION regression introduced in 1.5.0

CMakeLists.txt

@@ -34,9 +34,26 @@ SET(OPENJPEG_VERSION
   "${OPENJPEG_VERSION_MAJOR}.${OPENJPEG_VERSION_MINOR}.${OPENJPEG_VERSION_BUILD}")
 SET(PACKAGE_VERSION
   "${OPENJPEG_VERSION_MAJOR}.${OPENJPEG_VERSION_MINOR}.${OPENJPEG_VERSION_BUILD}")
+
+# Because autotools does not support X.Y notation for SOVERSION, we have to use
+# two numerorations, one for the openjpeg version and one for openjpeg soversion
+# version | soversion
+#   1.0   |   0
+#   1.1   |   1
+#   1.2   |   2
+#   1.3   |   3
+#   1.4   |   4
+#   1.5   |   5
+#   2.0   |   6
+# above is the recommendation by the OPJ team. If you really need to override this default,
+# you can specify your own OPENJPEG_SOVERSION at cmake configuration time:
+# cmake -DOPENJPEG_SOVERSION:STRING=42 /path/to/openjpeg
+if(NOT OPENJPEG_SOVERSION)
+  SET(OPENJPEG_SOVERSION 5)
+endif(NOT OPENJPEG_SOVERSION)
 SET(OPENJPEG_LIBRARY_PROPERTIES
   VERSION   "${OPENJPEG_VERSION_MAJOR}.${OPENJPEG_VERSION_MINOR}.${OPENJPEG_VERSION_BUILD}"
-  SOVERSION "${OPENJPEG_VERSION_MAJOR}"
+  SOVERSION "${OPENJPEG_SOVERSION}"
 )
 
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