diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1dadcb43..19d777a3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,8 +1,5 @@
-
-#
-# Copyright(c) 2015 Ruslan Baratov.
+# Copyright(c) 2019 spdlog
 # Distributed under the MIT License (http://opensource.org/licenses/MIT)
-#
 
 cmake_minimum_required(VERSION 3.1)
 project(spdlog VERSION 1.3.1 LANGUAGES CXX)
@@ -47,48 +44,36 @@ if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
     set(SPDLOG_MASTER_PROJECT ON)
 endif()
 
-option(SPDLOG_HEADER_ONLY "Header only version. Turn OFF to build as static lib" OFF)
+option(SPDLOG_STATIC_LIB "Build as static lib" OFF)
 option(SPDLOG_BUILD_EXAMPLES "Build examples" ${SPDLOG_MASTER_PROJECT})
 option(SPDLOG_BUILD_BENCH "Build benchmarks (Requires https://github.com/google/benchmark.git to be installed)" ON)
 option(SPDLOG_BUILD_TESTS "Build tests" ${SPDLOG_MASTER_PROJECT})
 option(SPDLOG_FMT_EXTERNAL "Use external fmt library instead of bundled" OFF)
 option(SPDLOG_INSTALL "Generate the install target." ${SPDLOG_MASTER_PROJECT})
 
-set(HEADER_BASE "${CMAKE_CURRENT_SOURCE_DIR}/include")
+set(HEADER_BASE "${CMAKE_CURRENT_SOURCE_DIR}/include/spdlog")
 
-if(SPDLOG_HEADER_ONLY)
-	add_definitions(-DSPDLOG_HEADER_ONLY)
-    add_library(spdlog INTERFACE)
-    add_library(spdlog::spdlog ALIAS spdlog)
-    target_include_directories(
-            spdlog
-            INTERFACE
-            "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>"
-    )
-
-else()
-	remove_definitions(-DSPDLOG_HEADER_ONLY)
-    file(GLOB SRC_FILES ${HEADER_BASE}/spdlog/impl/*.cpp)
+if(SPDLOG_STATIC_LIB)
+    add_definitions(-DSPDLOG_STATIC_LIB)
+    file(GLOB SRC_FILES ${HEADER_BASE}/impl/*.cpp)
     add_library(spdlog STATIC ${SRC_FILES})
-    add_library(spdlog::spdlog ALIAS spdlog)
-    target_include_directories(
-            spdlog
-            PUBLIC
-            "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>"
-    )
+    target_include_directories(spdlog PUBLIC  "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>")
+else()
+    add_library(spdlog INTERFACE)
+    target_include_directories(spdlog INTERFACE "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>")
 endif()
 
+add_library(spdlog::spdlog ALIAS spdlog)
+
 if(SPDLOG_FMT_EXTERNAL AND NOT TARGET fmt::fmt)
     find_package(fmt REQUIRED CONFIG)
 endif()
 
-
 if(SPDLOG_FMT_EXTERNAL)
     target_compile_definitions(spdlog INTERFACE SPDLOG_FMT_EXTERNAL)
     target_link_libraries(spdlog INTERFACE fmt::fmt)
 endif()
 
-
 if(SPDLOG_BUILD_EXAMPLES)
     add_subdirectory(example)
 endif()
@@ -105,9 +90,9 @@ endif()
 #---------------------------------------------------------------------------------------
 # install
 #---------------------------------------------------------------------------------------
-install(DIRECTORY ${HEADER_BASE}/spdlog DESTINATION include)
+install(DIRECTORY ${HEADER_BASE} DESTINATION include)
 
-if(NOT SPDLOG_HEADER_ONLY)
+if(SPDLOG_STATIC_LIB)
     install(TARGETS spdlog ARCHIVE DESTINATION lib)
 endif()
 
diff --git a/include/spdlog/async_logger.h b/include/spdlog/async_logger.h
index b0b644a4..0178b39d 100644
--- a/include/spdlog/async_logger.h
+++ b/include/spdlog/async_logger.h
@@ -65,6 +65,6 @@ private:
 };
 } // namespace spdlog
 
-#ifdef SPDLOG_HEADER_ONLY
+#ifndef SPDLOG_STATIC_LIB
 #include "spdlog/impl/async_logger.cpp"
-#endif // SPDLOG_HEADER_ONLY
+#endif
diff --git a/include/spdlog/common.h b/include/spdlog/common.h
index add4000b..0bcd03f5 100644
--- a/include/spdlog/common.h
+++ b/include/spdlog/common.h
@@ -23,10 +23,11 @@
 
 #include "spdlog/fmt/fmt.h"
 
-#ifdef SPDLOG_HEADER_ONLY
-#define SPDLOG_INLINE inline
-#else
+
+#ifdef SPDLOG_STATIC_LIB
 #define SPDLOG_INLINE
+#else
+#define SPDLOG_INLINE inline
 #endif
 
 // visual studio upto 2013 does not support noexcept nor constexpr
diff --git a/include/spdlog/details/file_helper.h b/include/spdlog/details/file_helper.h
index 9f7fceaa..6f9d7020 100644
--- a/include/spdlog/details/file_helper.h
+++ b/include/spdlog/details/file_helper.h
@@ -57,6 +57,6 @@ private:
 } // namespace details
 } // namespace spdlog
 
-#ifdef SPDLOG_HEADER_ONLY
+#ifndef SPDLOG_STATIC_LIB
 #include "spdlog/impl/file_helper.cpp"
-#endif // ! SPDLOG_HEADER_ONLY
+#endif
diff --git a/include/spdlog/details/log_msg.h b/include/spdlog/details/log_msg.h
index e9cacbb7..fea55a40 100644
--- a/include/spdlog/details/log_msg.h
+++ b/include/spdlog/details/log_msg.h
@@ -33,6 +33,6 @@ struct log_msg
 } // namespace details
 } // namespace spdlog
 
-#ifdef SPDLOG_HEADER_ONLY
+#ifndef SPDLOG_STATIC_LIB
 #include "spdlog/impl/log_msg.cpp"
-#endif //  SPDLOG_HEADER_ONLY
+#endif
diff --git a/include/spdlog/details/os.h b/include/spdlog/details/os.h
index 5f87f5fd..0467e944 100644
--- a/include/spdlog/details/os.h
+++ b/include/spdlog/details/os.h
@@ -88,6 +88,6 @@ void wbuf_to_utf8buf(const fmt::wmemory_buffer &wbuf, fmt::memory_buffer &target
 } // namespace details
 } // namespace spdlog
 
-#ifdef SPDLOG_HEADER_ONLY
+#ifndef SPDLOG_STATIC_LIB
 #include "spdlog/impl/os.cpp"
 #endif
diff --git a/include/spdlog/details/pattern_formatter.h b/include/spdlog/details/pattern_formatter.h
index 210efd23..8866b8bd 100644
--- a/include/spdlog/details/pattern_formatter.h
+++ b/include/spdlog/details/pattern_formatter.h
@@ -97,6 +97,6 @@ private:
 };
 } // namespace spdlog
 
-#ifdef SPDLOG_HEADER_ONLY
+#ifndef SPDLOG_STATIC_LIB
 #include "spdlog/impl/pattern_formatter.cpp"
 #endif
diff --git a/include/spdlog/details/registry.h b/include/spdlog/details/registry.h
index 93d35e87..d6f4dbea 100644
--- a/include/spdlog/details/registry.h
+++ b/include/spdlog/details/registry.h
@@ -101,6 +101,6 @@ private:
 } // namespace details
 } // namespace spdlog
 
-#ifdef SPDLOG_HEADER_ONLY
+#ifndef SPDLOG_STATIC_LIB
 #include "spdlog/impl/registry.cpp"
-#endif // SPDLOG_HEADER_ONLY
+#endif
diff --git a/include/spdlog/details/thread_pool.h b/include/spdlog/details/thread_pool.h
index 35578971..a1efcee6 100644
--- a/include/spdlog/details/thread_pool.h
+++ b/include/spdlog/details/thread_pool.h
@@ -11,6 +11,8 @@
 #include <vector>
 
 namespace spdlog {
+class async_logger;
+
 namespace details {
 
 using async_logger_ptr = std::shared_ptr<spdlog::async_logger>;
diff --git a/include/spdlog/impl/async_logger.cpp b/include/spdlog/impl/async_logger.cpp
index e915042e..eeae49f9 100644
--- a/include/spdlog/impl/async_logger.cpp
+++ b/include/spdlog/impl/async_logger.cpp
@@ -1,4 +1,4 @@
-#ifndef SPDLOG_HEADER_ONLY
+#ifdef SPDLOG_STATIC_LIB
 #include "spdlog/async_logger.h"
 #endif
 
diff --git a/include/spdlog/impl/file_helper.cpp b/include/spdlog/impl/file_helper.cpp
index 70a86eb8..eb8b9193 100644
--- a/include/spdlog/impl/file_helper.cpp
+++ b/include/spdlog/impl/file_helper.cpp
@@ -3,7 +3,7 @@
 // Distributed under the MIT License (http://opensource.org/licenses/MIT)
 //
 
-#ifndef SPDLOG_HEADER_ONLY
+#ifdef SPDLOG_STATIC_LIB
 #include "spdlog/details/file_helper.h"
 
 #endif
diff --git a/include/spdlog/impl/log_msg.cpp b/include/spdlog/impl/log_msg.cpp
index ec4f8642..e854a1ba 100644
--- a/include/spdlog/impl/log_msg.cpp
+++ b/include/spdlog/impl/log_msg.cpp
@@ -1,7 +1,7 @@
 #include "spdlog/details/os.h"
 #include "spdlog/sinks/sink.h"
 
-#ifndef SPDLOG_HEADER_ONLY
+#ifdef SPDLOG_STATIC_LIB
 #include "spdlog/details/log_msg.h"
 #endif
 
diff --git a/include/spdlog/impl/logger.cpp b/include/spdlog/impl/logger.cpp
index 7dcfc973..01316b64 100644
--- a/include/spdlog/impl/logger.cpp
+++ b/include/spdlog/impl/logger.cpp
@@ -1,4 +1,4 @@
-#ifndef SPDLOG_HEADER_ONLY
+#ifdef SPDLOG_STATIC_LIB
 #include "spdlog/logger.h"
 #endif
 
diff --git a/include/spdlog/impl/os.cpp b/include/spdlog/impl/os.cpp
index ecd5a611..e4260dba 100644
--- a/include/spdlog/impl/os.cpp
+++ b/include/spdlog/impl/os.cpp
@@ -2,7 +2,7 @@
 // Copyright(c) 2015 Gabi Melman.
 // Distributed under the MIT License (http://opensource.org/licenses/MIT)
 //
-#ifndef SPDLOG_HEADER_ONLY
+#ifdef SPDLOG_STATIC_LIB
 #include "spdlog/details/os.h"
 #endif
 
diff --git a/include/spdlog/impl/pattern_formatter.cpp b/include/spdlog/impl/pattern_formatter.cpp
index f1d43cf8..abcc7b36 100644
--- a/include/spdlog/impl/pattern_formatter.cpp
+++ b/include/spdlog/impl/pattern_formatter.cpp
@@ -3,9 +3,9 @@
 // Distributed under the MIT License (http://opensource.org/licenses/MIT)
 //
 
-#ifndef SPDLOG_HEADER_ONLY
+#ifdef SPDLOG_STATIC_LIB
 #include "spdlog/details/pattern_formatter.h"
-#endif // !SPDLOG_HEADER_ONLY
+#endif
 
 #include "spdlog/details/fmt_helper.h"
 #include "spdlog/details/log_msg.h"
diff --git a/include/spdlog/impl/registry.cpp b/include/spdlog/impl/registry.cpp
index ca0247eb..9a80aeea 100644
--- a/include/spdlog/impl/registry.cpp
+++ b/include/spdlog/impl/registry.cpp
@@ -2,7 +2,7 @@
 // Copyright(c) 2015 Gabi Melman.
 // Distributed under the MIT License (http://opensource.org/licenses/MIT)
 //
-#ifndef SPDLOG_HEADER_ONLY
+#ifdef SPDLOG_STATIC_LIB
 #include "spdlog/details/registry.h"
 #endif
 
diff --git a/include/spdlog/impl/sink.cpp b/include/spdlog/impl/sink.cpp
index 04adb9be..938fc73c 100644
--- a/include/spdlog/impl/sink.cpp
+++ b/include/spdlog/impl/sink.cpp
@@ -1,7 +1,7 @@
 #include "spdlog/common.h"
 #include "spdlog/details/pattern_formatter.h"
 
-#ifndef SPDLOG_HEADER_ONLY
+#ifdef SPDLOG_STATIC_LIB
 #include "spdlog/sinks/sink.h"
 #endif
 
diff --git a/include/spdlog/logger.h b/include/spdlog/logger.h
index 91371320..804abf33 100644
--- a/include/spdlog/logger.h
+++ b/include/spdlog/logger.h
@@ -340,6 +340,6 @@ protected:
 };
 } // namespace spdlog
 
-#ifdef SPDLOG_HEADER_ONLY
+#ifndef SPDLOG_STATIC_LIB
 #include "spdlog/impl/logger.cpp"
-#endif // SPDLOG_HEADER_ONLY
+#endif
diff --git a/include/spdlog/sinks/sink.h b/include/spdlog/sinks/sink.h
index bfa19e03..1fc1f1d7 100644
--- a/include/spdlog/sinks/sink.h
+++ b/include/spdlog/sinks/sink.h
@@ -41,6 +41,6 @@ protected:
 } // namespace sinks
 } // namespace spdlog
 
-#ifdef SPDLOG_HEADER_ONLY
+#ifndef SPDLOG_STATIC_LIB
 #include "spdlog/impl/sink.cpp"
-#endif // SPDLOG_HEADER_ONLY
+#endif