Add -fPIC when building vendorized static Boost libraries

Author: ecorm

README.md

@@ -401,7 +401,7 @@ the `-DCPPWAMP_OPT_HEADERS_ONLY` option is omitted.
 ```bash
 git clone https://github.com/ecorm/cppwamp
 cd cppwamp
-cmake -DCPPWAMP_OPT_VENDORIZE -S . -B ./_build
+cmake -DCPPWAMP_OPT_VENDORIZE=On -S . -B ./_build
 cmake --build ./_build
 cmake --install ./_build --prefix ./_stage/cppwamp
 ```

cmake/CppWAMPDependencies.cmake

@@ -96,7 +96,7 @@ function(cppwamp_build_boost source_dir build_dir install_dir)
     if(BUILD_SHARED_LIBS)
         list(APPEND CPPWAMP_BOOST_BUILD_ARGS "link=shared")
     else()
-        list(APPEND CPPWAMP_BOOST_BUILD_ARGS "link=static")
+        list(APPEND CPPWAMP_BOOST_BUILD_ARGS "link=static" "cxxflags=-fPIC")
     endif()
 
     list(APPEND CPPWAMP_BOOST_BUILD_ARGS "stage")

cppwamp/include/cppwamp/variant.hpp

@@ -481,22 +481,22 @@ CPPWAMP_API Variant::String typeNameOf();
 /// @name Non-member Output
 //------------------------------------------------------------------------------
 /// @{
-/** Outputs the given Array to the given output stream. */
+/** Outputs the given Array to the given output stream. @relates Variant */
 CPPWAMP_API std::ostream& operator<<(std::ostream& out, const Array& a);
 
-/** Outputs the given Object to the given output stream. */
+/** Outputs the given Object to the given output stream. @relates Variant */
 CPPWAMP_API std::ostream& operator<<(std::ostream& out, const Object& o);
 
-/** Outputs the given Variant to the given output stream. */
+/** Outputs the given Variant to the given output stream. @relates Variant */
 CPPWAMP_API std::ostream& operator<<(std::ostream& out, const Variant& v);
 
-/** Outputs the given Array to a new string. */
+/** Outputs the given Array to a new string. @relates Variant */
 CPPWAMP_API std::string toString(const Array& a);
 
-/** Outputs the given Object to a new string. */
+/** Outputs the given Object to a new string. @relates Variant */
 CPPWAMP_API std::string toString(const Object& o);
 
-/** Outputs the given Variant to a new string. */
+/** Outputs the given Variant to a new string. @relates Variant */
 CPPWAMP_API std::string toString(const Variant& v);
 /// @}