Fix support for icu4c url

See previous patch for how it was crashing.

Needed to improve version detection heuristic because with only trimming
-src suffix the version was detected as "2" and name as "icu4c-58".

nxdbom/__init__.py

@@ -295,7 +295,7 @@ def namever(url, failonerr=True): # -> (name, ver)  | None if !failonerr
             s = removesuffix(s, tail)
         for tail in ['-py2.7'] + ['-py3.%d' % _ for _ in range(20)]:
             s = removesuffix(s, tail)
-        for tail in ('-source',):
+        for tail in ('-source', '-src'):
             s = removesuffix(s, tail)
         return s
     url = del_tgztail(url)
@@ -332,15 +332,30 @@ def _namever(url, failonerr):
         url = unquote(m.group('f'))
 
     filename = basename(url)
-    # re.rsplit([-_], filename, 1)
-    m = re.search('[-_][^-_]*$', filename)
-    if m is not None:
-        name = filename[:m.start()]
-        ver  = filename[m.start()+1:]
-        if re.search(r'[0-9]', ver):
-            return name, ver
+
+    name   = filename
+    ver    = ''
+    dashed = False
+    while 1:
+        # re.rsplit([-_], name, 1)
+        m = re.search('[-_][^-_]*$', name)
+        if m is None:
+            break
+        dashed = True
+        v = name[m.start():]
+        v_ndigit = 0
+        for _ in v:
+            if _.isnumeric():
+                v_ndigit += 1
+        if v_ndigit < (len(v)-1) / 5:   # doesn't look like a version
+            break
+        name = name[:m.start()]
+        ver = v + ver
+    if dashed:
+        if not ver:
+            return name, None       # no version
         else:
-            return filename, None   # no version
+            return name, ver[1:]    # ver without leading '-'
 
     m = re.search(r'\.v.+$', filename)  # jpegsrc.v9d
     if m is not None:

nxdbom/nxdbom_test.py

@@ -42,6 +42,7 @@ from os.path import dirname, exists
     ('http://geolite.maxmind.com/download/geoip/database/GeoLite2-Country.tar.gz', 'GeoLite2-Country', None),
     ('http://downloadarchive.documentfoundation.org/libreoffice/old/5.2.4.2/rpm/x86_64/LibreOffice_5.2.4.2_Linux_x86-64_rpm.tar.gz',  'LibreOffice', '5.2.4.2'),
     ('http://www.cups.org/software/1.7.4/cups-1.7.4-source.tar.bz2',  'cups', '1.7.4'),
+    ('https://github.com/unicode-org/icu/releases/download/release-58-2/icu4c-58_2-src.tgz',  'icu4c', '58_2'),
 ])
 def test_namever(url, nameok, verok):
     assert nxdbom.namever(url) == (nameok, verok)