diff --git a/mail/base/moz.build b/mail/base/moz.build
index 4e8ff2fdb3..3b074fe1e7 100644
--- a/mail/base/moz.build
+++ b/mail/base/moz.build
@@ -66,4 +66,3 @@ for var in ("OS_CPPFLAGS", "OS_CXXFLAGS", "DEBUG", "OPTIMIZE", "FRAMEPTR"):
     cxx_flags += COMPILE_FLAGS[var] or []
 
 DEFINES["CXXFLAGS"] = " ".join(cxx_flags)
-DEFINES["CXXFLAGS"] += " -fPIC"
diff --git a/third_party/botan/botan.mozbuild b/third_party/botan/botan.mozbuild
index 0a03fd7838..a292b3bde9 100644
--- a/third_party/botan/botan.mozbuild
+++ b/third_party/botan/botan.mozbuild
@@ -27,7 +27,7 @@ if CONFIG['OS_ARCH'] == 'WINNT':
     botan_os = 'windows'
 elif CONFIG['OS_ARCH'] == 'Linux':
     botan_os = 'linux'
-    CXXFLAGS += ['-pthread', "-fPIC"]
+    CXXFLAGS += ['-pthread']
 else:
     botan_os = CONFIG['OS_ARCH'].lower()
 
diff --git a/third_party/rnp/moz.build b/third_party/rnp/moz.build
index e567ab5cbc..bb2cee86f7 100644
--- a/third_party/rnp/moz.build
+++ b/third_party/rnp/moz.build
@@ -79,8 +79,6 @@ if CONFIG["MZLA_SYSTEM_BZIP2"]:
 else:
     LOCAL_INCLUDES += ["../bzip2"]
 
-CXXFLAGS += ["-fPIC"]
-
 if CONFIG["CC_TYPE"] == "clang-cl":
     LOCAL_INCLUDES += [
         "../niwcompat",
diff --git a/third_party/rnpdefs.mozbuild b/third_party/rnpdefs.mozbuild
index dfaaac62ae..c253714e80 100644
--- a/third_party/rnpdefs.mozbuild
+++ b/third_party/rnpdefs.mozbuild
@@ -27,8 +27,6 @@ if CONFIG["CC_TYPE"] == "clang-cl":
         "-Wno-macro-redefined",  # 'WIN32_LEAN_AND_MEAN' macro redefined
     ]
     USE_STATIC_LIBS = True
-CFLAGS += ["-fPIC"]
-CXXFLAGS += ["-fPIC"]
 
 # MOZ_LIBSTDCXX_TARGET_VERSION should only be set for Taskcluster builds
 # targeting Linux. The below changes those builds to statically link to