ICU-20570 UInitOnce instances, add explicit initialization where it was missing.

icu4c/source/common/brkiter.cpp

@@ -277,7 +277,7 @@ ICUBreakIteratorService::~ICUBreakIteratorService() {}
 // defined in ucln_cmn.h
 U_NAMESPACE_END
 
-static icu::UInitOnce gInitOnceBrkiter;
+static icu::UInitOnce gInitOnceBrkiter = U_INITONCE_INITIALIZER;
 static icu::ICULocaleService* gService = NULL;
 
 

icu4c/source/common/characterproperties.cpp

@@ -38,8 +38,8 @@ UBool U_CALLCONV characterproperties_cleanup();
 constexpr int32_t NUM_INCLUSIONS = UPROPS_SRC_COUNT + UCHAR_INT_LIMIT - UCHAR_INT_START;
 
 struct Inclusion {
-    UnicodeSet  *fSet;
-    UInitOnce    fInitOnce;
+    UnicodeSet  *fSet = nullptr;
+    UInitOnce    fInitOnce = U_INITONCE_INITIALIZER;
 };
 Inclusion gInclusions[NUM_INCLUSIONS]; // cached getInclusions()
 

icu4c/source/common/normalizer2impl.h

@@ -245,9 +245,7 @@ private:
  */
 class U_COMMON_API Normalizer2Impl : public UObject {
 public:
-    Normalizer2Impl() : normTrie(NULL), fCanonIterData(NULL) {
-        fCanonIterDataInitOnce.reset();
-    }
+    Normalizer2Impl() : normTrie(NULL), fCanonIterData(NULL) { }
     virtual ~Normalizer2Impl();
 
     void init(const int32_t *inIndexes, const UCPTrie *inTrie,
@@ -723,7 +721,7 @@ private:
     const uint16_t *extraData;  // mappings and/or compositions for yesYes, yesNo & noNo characters
     const uint8_t *smallFCD;  // [0x100] one bit per 32 BMP code points, set if any FCD!=0
 
-    UInitOnce       fCanonIterDataInitOnce;
+    UInitOnce       fCanonIterDataInitOnce = U_INITONCE_INITIALIZER;
     CanonIterData  *fCanonIterData;
 };
 

icu4c/source/common/uresbund.cpp

@@ -47,7 +47,7 @@ TODO: This cache should probably be removed when the deprecated code is
       completely removed.
 */
 static UHashtable *cache = NULL;
-static icu::UInitOnce gCacheInitOnce;
+static icu::UInitOnce gCacheInitOnce = U_INITONCE_INITIALIZER;
 
 static UMutex *resbMutex() {
     static UMutex m = U_MUTEX_INITIALIZER;

icu4c/source/common/usprep.cpp

@@ -45,7 +45,7 @@ U_CDECL_BEGIN
 Static cache for already opened StringPrep profiles
 */
 static UHashtable *SHARED_DATA_HASHTABLE = NULL;
-static icu::UInitOnce gSharedDataInitOnce;
+static icu::UInitOnce gSharedDataInitOnce = U_INITONCE_INITIALIZER;
 
 static UMutex *usprepMutex() {
     static UMutex m = U_MUTEX_INITIALIZER;

icu4c/source/i18n/buddhcal.cpp

@@ -133,7 +133,7 @@ void BuddhistCalendar::timeToFields(UDate theTime, UBool quick, UErrorCode& stat
  */
 static UDate     gSystemDefaultCenturyStart       = DBL_MIN;
 static int32_t   gSystemDefaultCenturyStartYear   = -1;
-static icu::UInitOnce gBCInitOnce;
+static icu::UInitOnce gBCInitOnce = U_INITONCE_INITIALIZER;
 
 
 UBool BuddhistCalendar::haveDefaultCentury() const

icu4c/source/i18n/coll.cpp

@@ -67,7 +67,7 @@ static int32_t  availableLocaleListCount;
 static icu::ICULocaleService* gService = NULL;
 static icu::UInitOnce gServiceInitOnce = U_INITONCE_INITIALIZER;
 #endif
-static icu::UInitOnce gAvailableLocaleListInitOnce;
+static icu::UInitOnce gAvailableLocaleListInitOnce = U_INITONCE_INITIALIZER;
 
 /**
  * Release all static memory held by collator.

icu4c/source/i18n/csdetect.cpp

@@ -47,7 +47,7 @@ struct CSRecognizerInfo : public UMemory {
 U_NAMESPACE_END
 
 static icu::CSRecognizerInfo **fCSRecognizers = NULL;
-static icu::UInitOnce gCSRecognizersInitOnce;
+static icu::UInitOnce gCSRecognizersInitOnce = U_INITONCE_INITIALIZER;
 static int32_t fCSRecognizers_size = 0;
 
 U_CDECL_BEGIN

icu4c/source/i18n/olsontz.h

@@ -398,7 +398,7 @@ private:
     TimeArrayTimeZoneRule   **historicRules;
     int16_t             historicRuleCount;
     SimpleTimeZone      *finalZoneWithStartYear; // hack
-    UInitOnce           transitionRulesInitOnce;
+    UInitOnce           transitionRulesInitOnce = U_INITONCE_INITIALIZER;
 };
 
 inline int16_t