From 2a2d27086f68188082e68d291907bce6ce758025 Mon Sep 17 00:00:00 2001
From: David Cermak <cermak@espressif.com>
Date: Thu, 29 Jul 2021 16:16:15 +0200
Subject: [PATCH] esp_modem(0.1.9): Fix CMake3.5 build with no cxx_std_17
 feature

Older CMake (< 3.8, but still supported in IDF) doesn't support target_compile_features() for cxx_std_17.
If CMake doesn't know C++17 features, set it manually via comile options.
---
 components/esp_modem/CMakeLists.txt    | 11 ++++++++++-
 components/esp_modem/idf_component.yml |  2 +-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/components/esp_modem/CMakeLists.txt b/components/esp_modem/CMakeLists.txt
index f0c7e88e0..dea720007 100644
--- a/components/esp_modem/CMakeLists.txt
+++ b/components/esp_modem/CMakeLists.txt
@@ -33,7 +33,16 @@ idf_component_register(SRCS "${srcs}"
                     PRIV_INCLUDE_DIRS private_include
                     REQUIRES ${dependencies})
 
-target_compile_features(${COMPONENT_LIB} PRIVATE cxx_std_17)
+
+# If CMake doesn't know C++17 features, set it manually via comile options
+# esp-modem component requires C++17 internally, but older CMake (< 3.8, but still supported in IDF)
+# doesn't support target_compile_features() for cxx_std_17.
+get_property(cxx_known_features GLOBAL PROPERTY CMAKE_CXX_KNOWN_FEATURES)
+if ("cxx_std_17" IN_LIST cxx_known_features)
+    target_compile_features(${COMPONENT_LIB} PRIVATE cxx_std_17)
+else()
+    target_compile_options(${COMPONENT_LIB} PRIVATE "-std=gnu++17")
+endif()
 
 if(${target} STREQUAL "linux")
     # This is needed for ESP_LOGx() macros, as integer formats differ on ESP32(..) and x64
diff --git a/components/esp_modem/idf_component.yml b/components/esp_modem/idf_component.yml
index 338b6b957..31da00892 100644
--- a/components/esp_modem/idf_component.yml
+++ b/components/esp_modem/idf_component.yml
@@ -1,4 +1,4 @@
-version: "0.1.8"
+version: "0.1.9"
 description: esp modem
 dependencies:
   # Required IDF version