hg: jdk7u/jdk7u/langtools: 3 new changesets

[gnu.andrew at redhat.com]

Changeset: 4c27f6cf28e6
Author:    serb
Date:      2020-07-21 02:06 +0100
URL:       https://hg.openjdk.java.net/jdk7u/jdk7u/langtools/rev/4c27f6cf28e6

8220495: Update GIFlib library to the 5.1.8
Reviewed-by: prr

! THIRD_PARTY_README

Changeset: 2536160818d8
Author:    serb
Date:      2020-07-21 02:18 +0100
URL:       https://hg.openjdk.java.net/jdk7u/jdk7u/langtools/rev/2536160818d8

8230597: Update GIFlib library to the 5.2.1
Reviewed-by: prr, psadhukhan, jdv

! THIRD_PARTY_README

Changeset: 90cdd7bd8a50
Author:    serb
Date:      2020-07-21 03:18 +0100
URL:       https://hg.openjdk.java.net/jdk7u/jdk7u/langtools/rev/90cdd7bd8a50

8217676: Upgrade libpng to 1.6.37
Reviewed-by: prr, jdv, kcr

! THIRD_PARTY_README