android_support: fix lgamma and enable -Werror

We had -Werror enabled already for C++ files, but also enable it for C
files.

Bug: https://github.com/android-ndk/ndk/issues/793
Test: ./checkbuild.py && ./run_tests.py
Change-Id: If45b1fa2e737af2c6fe92f303f96f6c558417127

2 files changed, 43 insertions, 2 deletions

diff --git a/sources/android/support/Android.mk b/sources/android/support/Android.mk
index 2c50a47c3..1770c49d4 100644
--- a/sources/android/support/Android.mk
+++ b/sources/android/support/Android.mk
@@ -36,7 +36,9 @@ android_support_c_includes += \
 android_support_cflags += \
     -include freebsd-compat.h \
     -include openbsd-compat.h \
+    -include $(LOCAL_PATH)/src/support_preinclude.h \
     -D__BIONIC_BUILD_FOR_ANDROID_SUPPORT \
+    -Werror \
 
 android_support_sources := \
     $(BIONIC_PATH)/libc/bionic/c32rtomb.cpp \
@@ -70,7 +72,6 @@ android_support_sources := \
     $(BIONIC_PATH)/libm/upstream-freebsd/lib/msun/src/e_cosh.c \
     $(BIONIC_PATH)/libm/upstream-freebsd/lib/msun/src/e_exp.c \
     $(BIONIC_PATH)/libm/upstream-freebsd/lib/msun/src/e_hypot.c \
-    $(BIONIC_PATH)/libm/upstream-freebsd/lib/msun/src/e_lgamma.c \
     $(BIONIC_PATH)/libm/upstream-freebsd/lib/msun/src/e_log.c \
     $(BIONIC_PATH)/libm/upstream-freebsd/lib/msun/src/e_log10.c \
     $(BIONIC_PATH)/libm/upstream-freebsd/lib/msun/src/e_log2.c \
@@ -127,7 +128,6 @@ LOCAL_CFLAGS := $(android_support_cflags)
 LOCAL_CPPFLAGS := \
     -fvisibility-inlines-hidden \
     -std=c++11 \
-    -Werror \
 
 LOCAL_EXPORT_C_INCLUDES := $(android_support_export_c_includes)
 
diff --git a/sources/android/support/src/support_preinclude.h b/sources/android/support/src/support_preinclude.h
new file mode 100644
index 000000000..bf090b0d2
--- /dev/null
+++ b/sources/android/support/src/support_preinclude.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#pragma once
+
+// Declare cimag and creal for use by __ldexp_cexp. libandroid_runtime doesn't
+// really need __ldexp_cexp, but it does need __ldexp_exp, and both functions
+// are defined in the same C file. complex.h doesn't declare cimag/creal when
+// building libandroid_support, because the functions are only available
+// starting with M, and libandroid_support is compiled for the oldest supported
+// NDK API.
+//
+// The two functions are trivial (and have __builtin_{cimag,creal}
+// equivalents). Clang inlines calls to these functions even with -O0.
+double cimag(double _Complex z);
+double creal(double _Complex z);