Switch build configuration logic from DISABLE_TIFF to ENABLE_TIFF

* Autotools interface should be the same, but different ./configure --help
* For CMake, the option should be -DENABLE_TIFF=NO (default is YES)
* Use TIFF_ENABLED and CURL_ENABLED variables, based on option and outcome
* Reword some messages and add hints
* Move -DTIFF_ENABLED and -DCURL_ENABLED from global add_definitions()
  to target_compile_definitions(), which is recommended practice
* Minor spelling and style consistency around SQLITE_VERSION check

4 files changed, 30 insertions, 22 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b04c933e..be3303dc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -127,26 +127,31 @@ if(NOT SQLITE3_FOUND)
   message(SEND_ERROR "sqlite3 dependency not found!")
 endif()
 
-# Would build and run with older versons, but with horrible performance
+# Would build and run with older versions, but with horrible performance
 # See https://github.com/OSGeo/PROJ/issues/1718
-IF("${SQLITE3_VERSION}" VERSION_LESS "3.11")
+if("${SQLITE3_VERSION}" VERSION_LESS "3.11")
   message(SEND_ERROR "sqlite3 >= 3.11 required!")
-ENDIF()
+endif()
 
 ################################################################################
 # Check for libtiff
 ################################################################################
 
-option(DISABLE_TIFF "Disable TIFF support" OFF)
-mark_as_advanced(DISABLE_TIFF)
-if(DISABLE_TIFF)
-  message(WARNING "TIFF support has been disabled and will result in the inability to read some grids")
-else()
+option(ENABLE_TIFF "Enable TIFF support to read some grids" ON)
+mark_as_advanced(ENABLE_TIFF)
+set(TIFF_ENABLED FALSE)
+if(ENABLE_TIFF)
   find_package(TIFF REQUIRED)
-  if(NOT TIFF_FOUND)
-    message(SEND_ERROR "libtiff dependency not found!")
+  if(TIFF_FOUND)
+    set(TIFF_ENABLED TRUE)
+  else()
+    message(SEND_ERROR
+      "libtiff dependency not found! Use ENABLE_TIFF=OFF to force it off")
   endif()
-  add_definitions(-DTIFF_ENABLED)
+else()
+  message(WARNING
+    "TIFF support is not enabled and will result in the inability to read "
+    "some grids")
 endif()
 
 ################################################################################
@@ -154,12 +159,14 @@ endif()
 ################################################################################
 
 option(ENABLE_CURL "Enable Curl support" ON)
+set(CURL_ENABLED FALSE)
 if(ENABLE_CURL)
   find_package(CURL REQUIRED)
-  if(NOT CURL_FOUND)
+  if(CURL_FOUND)
+    set(CURL_ENABLED TRUE)
+  else()
     message(SEND_ERROR "curl dependency not found!")
   endif()
-  add_definitions(-DCURL_ENABLED)
 endif()
 
 ################################################################################
diff --git a/configure.ac b/configure.ac
index 88a5ba55..1759624c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -238,7 +238,7 @@ dnl ---------------------------------------------------------------------------
 
 if test "x$SQLITE3_CFLAGS$SQLITE3_LIBS" = "x" ; then
 
-    dnl Would build and run with older versons, but with horrible performance
+    dnl Would build and run with older versions, but with horrible performance
     dnl See https://github.com/OSGeo/PROJ/issues/1718
 
     PKG_CHECK_MODULES([SQLITE3], [sqlite3 >= 3.11])
@@ -256,12 +256,10 @@ dnl Check for libtiff
 dnl ---------------------------------------------------------------------------
 
 AC_ARG_ENABLE([tiff],
-              AS_HELP_STRING([--disable-tiff],
-                    [Disable TIFF support. Strongly discouraged !]),
-              [enable_tiff=no],
-              [enable_tiff=yes])
+              AS_HELP_STRING([--enable-tiff],
+                    [Enable TIFF support; strongly encouraged to read some grids [default=yes]]))
 
-if test "x$enable_tiff" = "xyes" -o "x$enable_tiff" = ""; then
+if test "x$enable_tiff" != "xno" -o "x$enable_tiff" = ""; then
     if test "x$TIFF_CFLAGS$TIFF_LIBS" = "x" ; then
         if $PKG_CONFIG libtiff; then
             PKG_CHECK_MODULES([TIFF], [libtiff])
diff --git a/src/lib_proj.cmake b/src/lib_proj.cmake
index 9200baba..e764aeee 100644
--- a/src/lib_proj.cmake
+++ b/src/lib_proj.cmake
@@ -406,12 +406,14 @@ endif()
 target_include_directories(${PROJ_CORE_TARGET} PRIVATE ${SQLITE3_INCLUDE_DIR})
 target_link_libraries(${PROJ_CORE_TARGET} ${SQLITE3_LIBRARY})
 
-if(NOT DISABLE_TIFF)
+if(TIFF_ENABLED)
+  target_compile_definitions(${PROJ_CORE_TARGET} PRIVATE -DTIFF_ENABLED)
   target_include_directories(${PROJ_CORE_TARGET} PRIVATE ${TIFF_INCLUDE_DIR})
   target_link_libraries(${PROJ_CORE_TARGET} ${TIFF_LIBRARY})
 endif()
 
-if(CURL_FOUND)
+if(CURL_ENABLED)
+  target_compile_definitions(${PROJ_CORE_TARGET} PRIVATE -DCURL_ENABLED)
   target_include_directories(${PROJ_CORE_TARGET} PRIVATE ${CURL_INCLUDE_DIR})
   target_link_libraries(${PROJ_CORE_TARGET} ${CURL_LIBRARY})
 endif()
diff --git a/test/unit/CMakeLists.txt b/test/unit/CMakeLists.txt
index 845d07e5..cd662865 100644
--- a/test/unit/CMakeLists.txt
+++ b/test/unit/CMakeLists.txt
@@ -153,8 +153,9 @@ set_property(TEST gie_self_tests
 add_executable(test_network
   main.cpp
   test_network.cpp)
-if(CURL_FOUND)
+if(CURL_ENABLED)
   include_directories(${CURL_INCLUDE_DIR})
+  target_compile_definitions(test_network PRIVATE -DCURL_ENABLED)
   target_link_libraries(test_network ${CURL_LIBRARY})
 endif()
 target_link_libraries(test_network