GeographicLib CMake minimal

0001-Add-CMake-aliases-to-allow-to-use-CMake-targets.patch

From 99c2d9fb36818f1a203477aab93f88d408bbf224 Mon Sep 17 00:00:00 2001
From: Romain Reignier <rre@robopec.com>
Date: Fri, 4 Sep 2020 11:57:41 +0200
Subject: [PATCH] Add CMake aliases to allow to use CMake targets

when GeographicLib is used as submodule/subdirectory.

See: https://cmake.org/cmake/help/v3.1/command/add_library.html#alias-libraries

In a CMake project including directly the GeographicLib source code as a
subdirectory with:
```
add_subdirectory(GeographicLib)
```
The GeographicLib targets are found properly with
`GeographicLib::GeographicLib`.
---
 src/CMakeLists.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 941bac5b..1bffa8b6 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -9,12 +9,15 @@ file (GLOB HEADERS
 # Define the library and specify whether it is shared or not.
 if (GEOGRAPHICLIB_SHARED_LIB)
   add_library (${PROJECT_SHARED_LIBRARIES} SHARED ${SOURCES} ${HEADERS})
+  add_library(${PROJECT_NAME}::${PROJECT_SHARED_LIBRARIES} ALIAS ${PROJECT_SHARED_LIBRARIES})
 endif ()
 if (GEOGRAPHICLIB_STATIC_LIB)
   add_library (${PROJECT_STATIC_LIBRARIES} STATIC ${SOURCES} ${HEADERS})
+  add_library(${PROJECT_NAME}::${PROJECT_STATIC_LIBRARIES} ALIAS ${PROJECT_STATIC_LIBRARIES})
 endif ()
 
 add_library (${PROJECT_INTERFACE_LIBRARIES} INTERFACE)
+add_library(${PROJECT_NAME}::${PROJECT_INTERFACE_LIBRARIES} ALIAS ${PROJECT_INTERFACE_LIBRARIES})
 target_link_libraries (${PROJECT_INTERFACE_LIBRARIES}
   INTERFACE ${PROJECT_LIBRARIES})
 
-- 
2.17.1

CMakeLists.txt

cmake_minimum_required(VERSION 3.1)
project(geographiclib_test)
add_subdirectory(GeographicLib)
add_executable(geo main.cpp)
target_link_libraries(geo GeographicLib::GeographicLib)

main.cpp

#include <iostream>
#include <GeographicLib/Geodesic.hpp>
int main()
{
    const GeographicLib::Geodesic& geod = GeographicLib::Geodesic::WGS84();
    double lat1 = 40.6, lon1 = -73.8, s12 = 5.5e6, azi1 = 51;
    double lat2, lon2;
    geod.Direct(lat1, lon1, azi1, s12, lat2, lon2);
    std::cout << lat2 << " " << lon2 << std::endl;
}