Rewrites for esp-idf

CMakeLists.txt

@@ -1,3 +1,4 @@
+if(NOT DEFINED IDF_TARGET)
 cmake_minimum_required(VERSION 3.8...3.26)
 
 # Fallback for using newer policies on CMake <3.12.
@@ -442,3 +443,12 @@ if (FMT_MASTER_PROJECT AND EXISTS ${gitignore})
   set(CPACK_RESOURCE_FILE_README ${PROJECT_SOURCE_DIR}/README.rst)
   include(CPack)
 endif ()
+else()
+idf_component_register(
+    SRCS
+        src/format.cc
+    INCLUDE_DIRS
+        include
+)
+set_property(TARGET ${COMPONENT_LIB} PROPERTY CXX_STANDARD 23)
+endif()

fmt.pri

@@ -0,0 +1 @@
+QMAKE_CXXFLAGS += -isystem $$PWD/include

fmt_src.pri

@@ -0,0 +1,4 @@
+HEADERS +=
+
+SOURCES += \
+    $$PWD/src/format.cc