From d2a2b3e4e99b3f661fc6167db332b3b2d9e50591 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Thu, 7 Nov 2019 13:44:35 +0100
Subject: [PATCH 1/2] Build: require SQLite 3.11 (refs #1718)

PROJ can build and run against older version (3.7 for example), but it has
been found that performance is horrible. With 3.11 (Ubuntu 16.04), it is
fine, so sets this as the minimum version.
---
 CMakeLists.txt          |  6 ++++++
 cmake/FindSqlite3.cmake | 13 +++++++++++++
 configure.ac            |  6 +++++-
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 63f516a3d2..2761e542e1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -127,6 +127,12 @@ if(NOT SQLITE3_FOUND)
   message(SEND_ERROR "sqlite3 dependency not found!")
 endif()
 
+# Would build and run with older versons, but with horrible performance
+# See https://github.com/OSGeo/PROJ/issues/1718
+IF("${SQLITE3_VERSION}" VERSION_LESS "3.11")
+  message(SEND_ERROR "sqlite3 >= 3.11 required!")
+ENDIF()
+
 ################################################################################
 # threading configuration
 ################################################################################
diff --git a/cmake/FindSqlite3.cmake b/cmake/FindSqlite3.cmake
index 4f1d909fcc..06cba0fbd7 100644
--- a/cmake/FindSqlite3.cmake
+++ b/cmake/FindSqlite3.cmake
@@ -10,6 +10,7 @@
 # and following variables are set:
 #    SQLITE3_INCLUDE_DIR
 #    SQLITE3_LIBRARY
+#    SQLITE3_VERSION
 
 
 # find_path and find_library normally search standard locations
@@ -53,9 +54,21 @@ if(SQLITE3_INCLUDE_DIR AND SQLITE3_LIBRARY)
   set(SQLITE3_FOUND TRUE)
 endif()
 
+# Extract version information from the header file
+if(SQLITE3_INCLUDE_DIR)
+    file(STRINGS ${SQLITE3_INCLUDE_DIR}/sqlite3.h _ver_line
+         REGEX "^#define SQLITE_VERSION  *\"[0-9]+\\.[0-9]+\\.[0-9]+\""
+         LIMIT_COUNT 1)
+    string(REGEX MATCH "[0-9]+\\.[0-9]+\\.[0-9]+"
+           SQLITE3_VERSION "${_ver_line}")
+    unset(_ver_line)
+endif()
+
+
 if(SQLITE3_FOUND)
   if(NOT SQLITE3_FIND_QUIETLY)
     message(STATUS "Found Sqlite3: ${SQLITE3_LIBRARY}")
+    message(STATUS "Sqlite3 version: ${SQLITE3_VERSION}")
   endif()
 
 else()
diff --git a/configure.ac b/configure.ac
index 7a6814b4b4..e9274621fa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -280,7 +280,11 @@ dnl Check for sqlite3 library and binary
 dnl ---------------------------------------------------------------------------
 
 if test "x$SQLITE3_CFLAGS$SQLITE3_LIBS" = "x" ; then
-    PKG_CHECK_MODULES([SQLITE3], [sqlite3 >= 3.7])
+
+    dnl Would build and run with older versons, but with horrible performance
+    dnl See https://github.com/OSGeo/PROJ/issues/1718
+
+    PKG_CHECK_MODULES([SQLITE3], [sqlite3 >= 3.11])
 fi
 AC_SUBST(SQLITE3_CFLAGS,$SQLITE3_CFLAGS)
 AC_SUBST(SQLITE3_LIBS,$SQLITE3_LIBS)

From 589f2104784ff88670f43fab899ece6d503ac027 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Thu, 7 Nov 2019 18:44:47 +0100
Subject: [PATCH 2/2] Doc: document build requirements

---
 docs/source/install.rst | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/docs/source/install.rst b/docs/source/install.rst
index d3c2fab60a..5f1013cda9 100644
--- a/docs/source/install.rst
+++ b/docs/source/install.rst
@@ -119,15 +119,20 @@ Compilation and installation from source code
 The classical way of installing PROJ is via the source code distribution. The
 most recent version is available from the :ref:`download page<current_release>`.
 
-PROJ requires C and C++11 compilers. It also requires SQLite3 (headers,
-library and executable).
-
 You will need that and at least the standard *proj-datumgrid* package for a
 successful installation.
 
 The following guides show how to compile and install the software using the
 Autotools and CMake build systems.
 
+Build requirements
+--------------------------------------------------------------------------------
+
+- C99 compiler
+- C++11 compiler
+- SQLite3 >= 3.11 (headers, library and executable)
+- GNU make for autotools build or CMake >= 3.5
+
 Autotools
 --------------------------------------------------------------------------------