libpng 1.6.2 works

git-svn-id: https://svn.r-project.org/R/trunk@62826 00db46b3-68df-0310-9c12-caf00c1e9a41
sync with R-patched

git-svn-id: https://svn.r-project.org/R/trunk@62829 00db46b3-68df-0310-9c12-caf00c1e9a41
avoid sqrtl (PR#15326)

git-svn-id: https://svn.r-project.org/R/trunk@62830 00db46b3-68df-0310-9c12-caf00c1e9a41
avoid sqrtl (PR#15326)

git-svn-id: https://svn.r-project.org/R/trunk@62832 00db46b3-68df-0310-9c12-caf00c1e9a41
new "safe" uniroot() =: unirootS()  [may change; see R-devel e-mail]

git-svn-id: https://svn.r-project.org/R/trunk@62834 00db46b3-68df-0310-9c12-caf00c1e9a41
monitor interval extension

git-svn-id: https://svn.r-project.org/R/trunk@62835 00db46b3-68df-0310-9c12-caf00c1e9a41
tweaks; note that Sig=0 keeps search interval

git-svn-id: https://svn.r-project.org/R/trunk@62836 00db46b3-68df-0310-9c12-caf00c1e9a41
Typo in external name

git-svn-id: https://svn.r-project.org/R/trunk@62837 00db46b3-68df-0310-9c12-caf00c1e9a41
Suppress warnings about missing globals on Windows

git-svn-id: https://svn.r-project.org/R/trunk@62838 00db46b3-68df-0310-9c12-caf00c1e9a41
Fix external call

git-svn-id: https://svn.r-project.org/R/trunk@62839 00db46b3-68df-0310-9c12-caf00c1e9a41