Cherry-pick: ICU-20325 Fix warnings about unknown pragma...
... when building with GCC in MSYS2 (Windows).
Upstream commit:
https://github.com/unicode-org/icu/commit/c3291233c4d384ec9642b1ccc368cfb9411e18db
Bug: 122841746
Test: N/A
Change-Id: Ie9a191ec88f9dec303dbe0ab0164074d4d48f18e
diff --git a/icu4c/source/i18n/erarules.h b/icu4c/source/i18n/erarules.h
index 4ed8640..8324b4c 100644
--- a/icu4c/source/i18n/erarules.h
+++ b/icu4c/source/i18n/erarules.h
@@ -18,8 +18,10 @@
// When building DLLs for Windows this is required even though no direct access leaks out of the i18n library.
// See digitlst.h, pluralaffix.h, datefmt.h, and others for similar examples.
#if U_PF_WINDOWS <= U_PLATFORM && U_PLATFORM <= U_PF_CYGWIN
+#if defined(_MSC_VER)
// Ignore warning 4661 as LocalPointerBase does not use operator== or operator!=
#pragma warning(suppress: 4661)
+#endif
template class U_I18N_API LocalPointerBase<int32_t>;
template class U_I18N_API LocalMemory<int32_t>;
#endif
diff --git a/icu4c/source/i18n/number_decimfmtprops.h b/icu4c/source/i18n/number_decimfmtprops.h
index f288b6e..4819cbd 100644
--- a/icu4c/source/i18n/number_decimfmtprops.h
+++ b/icu4c/source/i18n/number_decimfmtprops.h
@@ -21,8 +21,10 @@
// data member of CurrencyPluralInfoWrapper.
// (When building DLLs for Windows this is required.)
#if U_PF_WINDOWS <= U_PLATFORM && U_PLATFORM <= U_PF_CYGWIN
+#if defined(_MSC_VER)
// Ignore warning 4661 as LocalPointerBase does not use operator== or operator!=
#pragma warning(suppress: 4661)
+#endif
template class U_I18N_API LocalPointerBase<CurrencyPluralInfo>;
template class U_I18N_API LocalPointer<CurrencyPluralInfo>;
#endif
diff --git a/icu4c/source/i18n/number_patternmodifier.h b/icu4c/source/i18n/number_patternmodifier.h
index ea80d63..fcb3412 100644
--- a/icu4c/source/i18n/number_patternmodifier.h
+++ b/icu4c/source/i18n/number_patternmodifier.h
@@ -21,8 +21,10 @@
// data member of AdoptingModifierStore.
// (When building DLLs for Windows this is required.)
#if U_PF_WINDOWS <= U_PLATFORM && U_PLATFORM <= U_PF_CYGWIN
+#if defined(_MSC_VER)
// Ignore warning 4661 as LocalPointerBase does not use operator== or operator!=
#pragma warning(suppress: 4661)
+#endif
template class U_I18N_API LocalPointerBase<number::impl::AdoptingModifierStore>;
template class U_I18N_API LocalPointer<number::impl::AdoptingModifierStore>;
#endif
