diff --git a/include/fix_esp32c3.h b/include/fix_esp32c3.h
new file mode 100644
index 000000000..1964eb354
--- /dev/null
+++ b/include/fix_esp32c3.h
@@ -0,0 +1,40 @@
+/*
+  fix_esp32c3.h - fix esp32c3 toolchain
+
+  Copyright (C) 2021  Theo Arends
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+ * Xtensa toolchain declares `int32_t` as `int` but RISC-V toolchain
+ * declares `int32_t` as `long int` which causes compilation errors.
+ * 
+ * See:
+ *   https://github.com/espressif/esp-idf/issues/6906
+ *   https://github.com/espressif/arduino-esp32/issues/5086
+ * 
+ * You need to add the following lines in `build_flags`:      
+ *                            -I$PROJECT_DIR/include
+ *                            -include "fix_esp32c3.h"
+ */
+#ifdef __riscv
+
+#undef __INT32_TYPE__
+#define __INT32_TYPE__      int
+
+#undef __UINT32_TYPE__
+#define __UINT32_TYPE__     unsigned int
+
+#endif // __riscv