In addition to Marco's suggestions,

Shading of leaves during the dry long dry seasons helps reduce water loss via transpiration,

Woody plants have deeply penetrating or extensive tap roots to seek out water at even great depth during the dry months,

Some plants e.g Acacias are armed with prickles making it difficult for some animals to use them as a source of feed.  Some plants also secrete poisonous compound to repel animals and insects,

Indehiscent fruits with numerous seed to promote effective dispersal are also very important adaptations.

Many of the local grain crops in the region such as sorghum and millet follow the C4- photosynthetic pathway (capable of converting very high light intensities more efficiently than is possible in   C3 crops).

Very interesting answers, thanks